diff --git a/src/Controller/Admin/AccommodationBooking/SendAccessLinkController.php b/src/Controller/Admin/AccommodationBooking/SendAccessLinkController.php
index bba6f71..c8fcefa 100644
--- a/src/Controller/Admin/AccommodationBooking/SendAccessLinkController.php
+++ b/src/Controller/Admin/AccommodationBooking/SendAccessLinkController.php
@@ -35,6 +35,14 @@ class SendAccessLinkController extends AbstractController
                 throw $this->createAccessDeniedException('Invalid CSRF token.');
             }
 
+            // Older bookings can still be missing their contact data. Sending would be
+            // silently skipped further down, so say so instead of reporting success.
+            if (null === $booking->getEmail() || '' === trim($booking->getEmail())) {
+                $this->addFlash('error', 'Für diese Buchung ist keine E-Mail-Adresse hinterlegt. Bitte ergänze sie, um den Zugangslink zu senden.');
+
+                return new HxRedirectResponse($this->generateUrl('app_admin_accommodationbooking_edit', ['id' => $booking->getId()]));
+            }
+
             $this->bookingService->sendCustomerConfirmationEmail($booking);
 
             $this->addFlash('success', 'Der Zugangslink wurde dem Kunden per E-Mail zugestellt.');
diff --git a/src/Controller/Groups/OfferController.php b/src/Controller/Groups/OfferController.php
index abcd424..e1e53fb 100644
--- a/src/Controller/Groups/OfferController.php
+++ b/src/Controller/Groups/OfferController.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace App\Controller\Groups;
 
 use App\Entity\Groups\AccommodationBooking;
+use App\Form\Model\OfferAcceptDto;
 use App\Form\OfferAcceptConfirmationType;
 use App\Htmx\HxTrait;
 use App\Model\AccommodationBookingContext;
@@ -97,13 +98,16 @@ class OfferController extends AbstractController
             return $this->redirectToOfferPage($request, $uuid);
         }
 
-        $confirmationForm = $this->createForm(OfferAcceptConfirmationType::class, null, [
+        $dto = new OfferAcceptDto(remarks: $booking->getRemarks());
+        $confirmationForm = $this->createForm(OfferAcceptConfirmationType::class, $dto, [
             'terms_url' => $this->termsUrlProvider->forAccommodation($booking->getAccommodation()),
         ]);
         $confirmationForm->handleRequest($request);
 
         if ($confirmationForm->isSubmitted() && $confirmationForm->isValid()) {
-            $this->bookingService->acceptBooking($booking);
+            // The textarea is prefilled, so the submitted value is the complete remark —
+            // an emptied field arrives as null and must clear the stored one, not keep it.
+            $this->bookingService->acceptBooking($booking, $dto->remarks ?? '');
             $this->addFlash('success', 'Deine Buchung ist bestätigt.');
 
             return $this->redirectToOfferPage($request, $uuid);
diff --git a/src/Entity/Groups/AccommodationBooking.php b/src/Entity/Groups/AccommodationBooking.php
index 86c5965..0bdf9d6 100644
--- a/src/Entity/Groups/AccommodationBooking.php
+++ b/src/Entity/Groups/AccommodationBooking.php
@@ -109,9 +109,15 @@ class AccommodationBooking implements BlameableEntityInterface, TimestampableEnt
     #[Assert\NotBlank(groups: ['edit'])]
     private ?string $lastName = null;
 
+    /**
+     * The `offer` group covers the one field a customer-facing booking cannot do without:
+     * the access link and every notification are addressed to it. It is enforced on
+     * creation as soon as the booking is not a draft, while `edit` additionally demands
+     * the rest of the contact data.
+     */
     #[ORM\Column(length: 255, nullable: true)]
-    #[Assert\NotBlank(groups: ['edit'])]
-    #[Assert\Email(groups: ['edit'])]
+    #[Assert\NotBlank(groups: ['edit', 'offer'])]
+    #[Assert\Email(groups: ['edit', 'offer'])]
     private ?string $email = null;
 
     #[ORM\Column(length: 50, nullable: true)]
diff --git a/src/Form/Admin/Groups/AccommodationBookingCreateType.php b/src/Form/Admin/Groups/AccommodationBookingCreateType.php
index 23ee17c..f8046b6 100644
--- a/src/Form/Admin/Groups/AccommodationBookingCreateType.php
+++ b/src/Form/Admin/Groups/AccommodationBookingCreateType.php
@@ -10,9 +10,11 @@ use App\Enum\Groups\AccommodationBookingStatus;
 use Symfony\Bridge\Doctrine\Form\Type\EntityType;
 use Symfony\Component\Form\AbstractType;
 use Symfony\Component\Form\Extension\Core\Type\DateType;
+use Symfony\Component\Form\Extension\Core\Type\EmailType;
 use Symfony\Component\Form\Extension\Core\Type\EnumType;
 use Symfony\Component\Form\Extension\Core\Type\IntegerType;
 use Symfony\Component\Form\FormBuilderInterface;
+use Symfony\Component\Form\FormInterface;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
 /**
@@ -57,6 +59,13 @@ class AccommodationBookingCreateType extends AbstractType
                 ],
                 'choice_label' => fn (AccommodationBookingStatus $status) => $status->label(),
             ])
+            // Not marked required in HTML: a draft may be saved without it, and the
+            // validation group below enforces it for everything else.
+            ->add('email', EmailType::class, [
+                'label' => 'E-Mail',
+                'required' => false,
+                'help' => 'Für ein Angebot erforderlich — der Zugangslink und alle Benachrichtigungen gehen an diese Adresse.',
+            ])
         ;
     }
 
@@ -64,6 +73,15 @@ class AccommodationBookingCreateType extends AbstractType
     {
         $resolver->setDefaults([
             'data_class' => AccommodationBooking::class,
+            // A draft is a scratch record, but anything the customer can be pointed at
+            // needs a reachable address — see the `offer` group on the entity. The rest of
+            // the contact data is collected on the edit page, which validates `edit`.
+            'validation_groups' => static function (FormInterface $form): array {
+                /** @var AccommodationBooking $booking */
+                $booking = $form->getData();
+
+                return $booking->isDraft() ? ['Default'] : ['Default', 'offer'];
+            },
         ]);
     }
 }
diff --git a/src/Form/Model/OfferAcceptDto.php b/src/Form/Model/OfferAcceptDto.php
new file mode 100644
index 0000000..109c501
--- /dev/null
+++ b/src/Form/Model/OfferAcceptDto.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Form\Model;
+
+use Symfony\Component\Validator\Constraints as Assert;
+
+/**
+ * Carries what the offer acceptance modal submits: the AGB confirmation and an
+ * optional remark. `remarks` is prefilled from the booking, so whatever comes back
+ * is the full value the customer wants stored — an emptied textarea means "clear it".
+ */
+class OfferAcceptDto
+{
+    public function __construct(
+        #[Assert\IsTrue(message: 'Bitte akzeptiere die AGB, um die Buchung abzuschließen.')]
+        public bool $termsAccepted = false,
+        #[Assert\Length(max: 2000, maxMessage: 'Die Anmerkungen dürfen maximal {{ limit }} Zeichen lang sein.')]
+        public ?string $remarks = null,
+    ) {
+    }
+}
diff --git a/src/Form/OfferAcceptConfirmationType.php b/src/Form/OfferAcceptConfirmationType.php
index fefcf33..8d705ab 100644
--- a/src/Form/OfferAcceptConfirmationType.php
+++ b/src/Form/OfferAcceptConfirmationType.php
@@ -4,14 +4,15 @@ declare(strict_types=1);
 
 namespace App\Form;
 
+use App\Form\Model\OfferAcceptDto;
 use Symfony\Component\Form\AbstractType;
 use Symfony\Component\Form\Extension\Core\Type\CheckboxType;
+use Symfony\Component\Form\Extension\Core\Type\TextareaType;
 use Symfony\Component\Form\FormBuilderInterface;
 use Symfony\Component\OptionsResolver\OptionsResolver;
-use Symfony\Component\Validator\Constraints\IsTrue;
 
 /**
- * @extends AbstractType<null>
+ * @extends AbstractType<OfferAcceptDto>
  */
 class OfferAcceptConfirmationType extends AbstractType
 {
@@ -22,19 +23,28 @@ class OfferAcceptConfirmationType extends AbstractType
             htmlspecialchars($options['terms_url'], ENT_QUOTES, 'UTF-8')
         );
 
-        $builder->add('termsAccepted', CheckboxType::class, [
-            'label' => sprintf('Ich habe die %s gelesen und bin damit einverstanden, dass eine kostenpflichtige Buchung zustande kommt.', $termsLink),
-            'label_html' => true,
-            'mapped' => false,
-            'required' => true,
-            'constraints' => [
-                new IsTrue(message: 'Bitte akzeptiere die AGB, um die Buchung abzuschließen.'),
-            ],
-        ]);
+        $builder
+            ->add('remarks', TextareaType::class, [
+                'label' => 'Anmerkungen (optional)',
+                'required' => false,
+                'attr' => [
+                    'rows' => 4,
+                    'maxlength' => 2000,
+                ],
+            ])
+            ->add('termsAccepted', CheckboxType::class, [
+                'label' => sprintf('Ich habe die %s gelesen und bin damit einverstanden, dass eine kostenpflichtige Buchung zustande kommt.', $termsLink),
+                'label_html' => true,
+                'required' => true,
+            ])
+        ;
     }
 
     public function configureOptions(OptionsResolver $resolver): void
     {
+        $resolver->setDefaults([
+            'data_class' => OfferAcceptDto::class,
+        ]);
         $resolver->setRequired('terms_url');
         $resolver->setAllowedTypes('terms_url', 'string');
     }
diff --git a/src/Service/AccommodationBookingService.php b/src/Service/AccommodationBookingService.php
index 9c9dc98..0af0027 100644
--- a/src/Service/AccommodationBookingService.php
+++ b/src/Service/AccommodationBookingService.php
@@ -387,14 +387,28 @@ class AccommodationBookingService
     /**
      * All accommodation mail is sent from the group desk address so customer replies
      * land there rather than in the general inbox.
+     *
+     * A booking can legitimately have no email yet (drafts, and offers created without
+     * contact data), so a missing recipient is logged and skipped rather than thrown:
+     * the caller's own work — accepting an offer, for instance — is already done and
+     * must not fail over an undeliverable notification.
      */
     private function sendBookingEmail(
         AccommodationBooking $booking,
-        string $to,
+        ?string $to,
         string $subject,
         string $template,
         string $errorMessage,
     ): void {
+        if (null === $to || '' === trim($to)) {
+            $this->logger->warning($errorMessage, [
+                'booking_id' => $booking->getId(),
+                'error' => 'No recipient email address on the booking.',
+            ]);
+
+            return;
+        }
+
         try {
             $this->mailer->createAndSendEmail(
                 [
@@ -486,13 +500,21 @@ class AccommodationBookingService
      * only the status moves to Bestätigt, so an offer-originated booking remains
      * distinguishable from a direct one.
      * Idempotent — a no-op (including no emails) if the offer is not open any more.
+     *
+     * @param ?string $remarks null leaves the stored remark untouched, a string replaces it,
+     *                         an empty string clears it
      */
-    public function acceptBooking(AccommodationBooking $booking): void
+    public function acceptBooking(AccommodationBooking $booking, ?string $remarks = null): void
     {
         if (!$booking->isInquiry() || !$booking->isOpen()) {
             return;
         }
 
+        if (null !== $remarks) {
+            $trimmed = trim($remarks);
+            $booking->setRemarks('' === $trimmed ? null : $trimmed);
+        }
+
         $booking->setStatus(AccommodationBookingStatus::Accepted);
         $booking->setAcceptedAt(new \DateTimeImmutable());
         $this->entityManager->flush();
diff --git a/templates/admin/accommodation_booking/modal_create.html.twig b/templates/admin/accommodation_booking/modal_create.html.twig
index 1db37b4..b3bd912 100644
--- a/templates/admin/accommodation_booking/modal_create.html.twig
+++ b/templates/admin/accommodation_booking/modal_create.html.twig
@@ -18,6 +18,9 @@
         <div class="lg:col-span-2">
             {{ form_row(form.status) }}
         </div>
+        <div class="lg:col-span-2">
+            {{ form_row(form.email) }}
+        </div>
     </div>
     <div class="flex justify-end pt-8">
         <button type="submit" class="button button--primary button--small">
diff --git a/templates/email/offer_accepted.html.twig b/templates/email/offer_accepted.html.twig
index 7c1cd55..adc5f4a 100644
--- a/templates/email/offer_accepted.html.twig
+++ b/templates/email/offer_accepted.html.twig
@@ -24,4 +24,9 @@
             <td>{{ booking.dateTo|date('d.m.Y') }}</td>
         </tr>
     </table>
+
+    {% if booking.remarks %}
+        <h2>Anmerkungen</h2>
+        <p>{{ booking.remarks|nl2br }}</p>
+    {% endif %}
 {% endblock %}
diff --git a/templates/email/offer_accepted_customer.html.twig b/templates/email/offer_accepted_customer.html.twig
index 8acc146..03430f3 100644
--- a/templates/email/offer_accepted_customer.html.twig
+++ b/templates/email/offer_accepted_customer.html.twig
@@ -46,6 +46,14 @@
         </tr>
     </table>
 
+    {% if booking.remarks %}
+        <h2>
+            Anmerkungen
+        </h2>
+
+        <p>{{ booking.remarks|nl2br }}</p>
+    {% endif %}
+
     <p>
         Bei Fragen antworte einfach auf diese E-Mail.
     </p>
diff --git a/templates/groups/booking/_offer_accept_confirmation_modal.html.twig b/templates/groups/booking/_offer_accept_confirmation_modal.html.twig
index 780d987..9d69f1e 100644
--- a/templates/groups/booking/_offer_accept_confirmation_modal.html.twig
+++ b/templates/groups/booking/_offer_accept_confirmation_modal.html.twig
@@ -4,7 +4,8 @@
 
 {% block content %}
     {% from '_partials/_validation_errors.html.twig' import validation_alert %}
-    {{ validation_alert(confirmationForm, 'Bitte akzeptiere die AGB, um die Buchung abzuschließen.', false) }}
+    {# Generic title: both fields can fail, and each renders its own message inline. #}
+    {{ validation_alert(confirmationForm, null, false) }}
 
     <p class="mb-6">
         Möchtest du dieses Angebot jetzt verbindlich buchen?
@@ -17,6 +18,7 @@
             'hx-swap': 'outerHTML',
         }
     }) }}
+        {{ form_row(confirmationForm.remarks) }}
         {{ form_row(confirmationForm.termsAccepted) }}
 
         <div class="mt-6 flex flex-col space-y-4 md:flex-row md:space-y-0 justify-between">
diff --git a/tests/Controller/Groups/OfferControllerTest.php b/tests/Controller/Groups/OfferControllerTest.php
index c7a6372..61c8e49 100644
--- a/tests/Controller/Groups/OfferControllerTest.php
+++ b/tests/Controller/Groups/OfferControllerTest.php
@@ -8,6 +8,7 @@ use App\Controller\Groups\OfferController;
 use App\Entity\Groups\Accommodation;
 use App\Entity\Groups\AccommodationBooking;
 use App\Enum\Groups\AccommodationBookingStatus;
+use App\Form\Model\OfferAcceptDto;
 use App\Repository\Groups\AccommodationBookingRepository;
 use App\Service\AccommodationBookingBreakdownCalculator;
 use App\Service\AccommodationBookingLinkSigner;
@@ -208,6 +209,7 @@ class OfferControllerTest extends TestCase
     {
         $booking = new AccommodationBooking();
         $booking->setStatus(AccommodationBookingStatus::Open);
+        $booking->setRemarks("Bitte Zimmer im EG\nDanke!");
 
         $bookingRepository = $this->createMock(AccommodationBookingRepository::class);
         $bookingRepository->method('findOneBy')->with(['uuid' => $booking->getUuid()])->willReturn($booking);
@@ -233,12 +235,17 @@ class OfferControllerTest extends TestCase
         self::assertSame('groups/booking/_offer_accept_confirmation_modal.html.twig', $controller->renderedView);
         self::assertSame($booking, $controller->renderedParameters['booking']);
         self::assertSame($confirmationForm, $controller->renderedParameters['confirmationForm']);
+
+        self::assertInstanceOf(OfferAcceptDto::class, $controller->formData);
+        self::assertSame("Bitte Zimmer im EG\nDanke!", $controller->formData->remarks, 'the stored remark is prefilled into the modal');
+        self::assertFalse($controller->formData->termsAccepted);
     }
 
     public function testConfirmPostValidAcceptsBookingAndRedirects(): void
     {
         $booking = new AccommodationBooking();
         $booking->setStatus(AccommodationBookingStatus::Open);
+        $booking->setRemarks('Bitte Zimmer im EG');
 
         $bookingRepository = $this->createMock(AccommodationBookingRepository::class);
         $bookingRepository->method('findOneBy')->willReturn($booking);
@@ -247,7 +254,7 @@ class OfferControllerTest extends TestCase
         $linkSigner->method('isSessionAuthorized')->willReturn(true);
 
         $bookingService = $this->createMock(AccommodationBookingService::class);
-        $bookingService->expects(self::once())->method('acceptBooking')->with($booking);
+        $bookingService->expects(self::once())->method('acceptBooking')->with($booking, 'Bitte Zimmer im EG');
 
         $confirmationForm = $this->createMock(FormInterface::class);
         $confirmationForm->method('handleRequest')->willReturnSelf();
@@ -282,7 +289,8 @@ class OfferControllerTest extends TestCase
         $linkSigner->method('isSessionAuthorized')->willReturn(true);
 
         $bookingService = $this->createMock(AccommodationBookingService::class);
-        $bookingService->expects(self::once())->method('acceptBooking')->with($booking);
+        // No remark on the booking and none submitted: the empty string clears rather than keeps.
+        $bookingService->expects(self::once())->method('acceptBooking')->with($booking, '');
 
         $confirmationForm = $this->createMock(FormInterface::class);
         $confirmationForm->method('handleRequest')->willReturnSelf();
@@ -412,6 +420,8 @@ final class TestableOfferController extends OfferController
     /** @var array<string, mixed> */
     public array $renderedParameters = [];
 
+    public mixed $formData = null;
+
     public function __construct(
         AccommodationBookingRepository $bookingRepository,
         AccommodationBookingLinkSigner $linkSigner,
@@ -430,6 +440,8 @@ final class TestableOfferController extends OfferController
 
     protected function createForm(string $type, mixed $data = null, array $options = []): FormInterface
     {
+        $this->formData = $data;
+
         return $this->confirmationForm ?? throw new \LogicException('No confirmation form mock configured for this test.');
     }
 
diff --git a/tests/Form/Admin/Groups/AccommodationBookingCreateTypeTest.php b/tests/Form/Admin/Groups/AccommodationBookingCreateTypeTest.php
new file mode 100644
index 0000000..60abc0a
--- /dev/null
+++ b/tests/Form/Admin/Groups/AccommodationBookingCreateTypeTest.php
@@ -0,0 +1,109 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Form\Admin\Groups;
+
+use App\Entity\Groups\AccommodationBooking;
+use App\Enum\Groups\AccommodationBookingStatus;
+use App\Form\Admin\Groups\AccommodationBookingCreateType;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Form\FormInterface;
+use Symfony\Component\OptionsResolver\OptionsResolver;
+use Symfony\Component\Validator\Constraints\Email;
+use Symfony\Component\Validator\Constraints\EmailValidator;
+use Symfony\Component\Validator\ConstraintValidatorFactory;
+use Symfony\Component\Validator\Validation;
+
+class AccommodationBookingCreateTypeTest extends TestCase
+{
+    public function testDraftsAreValidatedWithoutTheOfferGroup(): void
+    {
+        self::assertSame(['Default'], $this->resolveValidationGroups(AccommodationBookingStatus::Draft));
+    }
+
+    public function testOffersAddTheOfferGroup(): void
+    {
+        self::assertSame(['Default', 'offer'], $this->resolveValidationGroups(AccommodationBookingStatus::Open));
+    }
+
+    public function testDraftCanBeCreatedWithoutAnEmail(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Draft);
+
+        $violations = $this->validate($booking, $this->resolveValidationGroups(AccommodationBookingStatus::Draft));
+
+        self::assertCount(0, $violations);
+    }
+
+    public function testOfferCannotBeCreatedWithoutAnEmail(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Open);
+
+        $violations = $this->validate($booking, $this->resolveValidationGroups(AccommodationBookingStatus::Open));
+
+        $properties = array_map(static fn ($violation) => $violation->getPropertyPath(), iterator_to_array($violations));
+
+        self::assertSame(['email'], $properties, 'only the address is enforced here — the rest of the contact data belongs to the edit form');
+    }
+
+    public function testOfferRejectsAMalformedEmail(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Open);
+        $booking->setEmail('not-an-address');
+
+        $violations = $this->validate($booking, $this->resolveValidationGroups(AccommodationBookingStatus::Open));
+
+        self::assertCount(1, $violations);
+        self::assertSame('email', $violations[0]->getPropertyPath());
+    }
+
+    public function testOfferWithAnEmailIsValid(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Open);
+        $booking->setEmail('customer@example.com');
+
+        $violations = $this->validate($booking, $this->resolveValidationGroups(AccommodationBookingStatus::Open));
+
+        self::assertCount(0, $violations);
+    }
+
+    /**
+     * @return string[]
+     */
+    private function resolveValidationGroups(AccommodationBookingStatus $status): array
+    {
+        $resolver = new OptionsResolver();
+        (new AccommodationBookingCreateType())->configureOptions($resolver);
+
+        $booking = new AccommodationBooking();
+        $booking->setStatus($status);
+
+        $form = $this->createMock(FormInterface::class);
+        $form->method('getData')->willReturn($booking);
+
+        return ($resolver->resolve()['validation_groups'])($form);
+    }
+
+    /**
+     * @param string[] $groups
+     */
+    private function validate(AccommodationBooking $booking, array $groups): \Symfony\Component\Validator\ConstraintViolationListInterface
+    {
+        // The app configures email_validation_mode: html5 globally (config/packages/validator.yaml);
+        // the standalone builder would otherwise fall back to the deprecated "loose" mode.
+        $validatorFactory = new ConstraintValidatorFactory([
+            EmailValidator::class => new EmailValidator(Email::VALIDATION_MODE_HTML5),
+        ]);
+
+        return Validation::createValidatorBuilder()
+            ->enableAttributeMapping()
+            ->setConstraintValidatorFactory($validatorFactory)
+            ->getValidator()
+            ->validate($booking, null, $groups);
+    }
+}
diff --git a/tests/Form/Model/OfferAcceptDtoTest.php b/tests/Form/Model/OfferAcceptDtoTest.php
new file mode 100644
index 0000000..5653c8c
--- /dev/null
+++ b/tests/Form/Model/OfferAcceptDtoTest.php
@@ -0,0 +1,54 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Tests\Form\Model;
+
+use App\Form\Model\OfferAcceptDto;
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Validator\Validation;
+use Symfony\Component\Validator\Validator\ValidatorInterface;
+
+class OfferAcceptDtoTest extends TestCase
+{
+    public function testAcceptedTermsWithoutRemarksIsValid(): void
+    {
+        $violations = $this->validator()->validate(new OfferAcceptDto(termsAccepted: true));
+
+        self::assertCount(0, $violations);
+    }
+
+    public function testUncheckedTermsAreRejected(): void
+    {
+        $violations = $this->validator()->validate(new OfferAcceptDto(remarks: 'Bitte Zimmer im EG'));
+
+        self::assertCount(1, $violations);
+        self::assertSame('termsAccepted', $violations[0]->getPropertyPath());
+        self::assertSame('Bitte akzeptiere die AGB, um die Buchung abzuschließen.', $violations[0]->getMessage());
+    }
+
+    public function testRemarksAreCappedAt2000Characters(): void
+    {
+        $dto = new OfferAcceptDto(termsAccepted: true, remarks: str_repeat('a', 2001));
+
+        $violations = $this->validator()->validate($dto);
+
+        self::assertCount(1, $violations);
+        self::assertSame('remarks', $violations[0]->getPropertyPath());
+        self::assertSame('Die Anmerkungen dürfen maximal 2000 Zeichen lang sein.', $violations[0]->getMessage());
+    }
+
+    public function testRemarksAtTheLimitAreAccepted(): void
+    {
+        $dto = new OfferAcceptDto(termsAccepted: true, remarks: str_repeat('a', 2000));
+
+        self::assertCount(0, $this->validator()->validate($dto));
+    }
+
+    private function validator(): ValidatorInterface
+    {
+        return Validation::createValidatorBuilder()
+            ->enableAttributeMapping()
+            ->getValidator();
+    }
+}
diff --git a/tests/Service/AccommodationBookingServiceTest.php b/tests/Service/AccommodationBookingServiceTest.php
index 7db5fe6..7d38371 100644
--- a/tests/Service/AccommodationBookingServiceTest.php
+++ b/tests/Service/AccommodationBookingServiceTest.php
@@ -294,6 +294,89 @@ class AccommodationBookingServiceTest extends TestCase
         self::assertNotNull($booking->getAcceptedAt());
     }
 
+    public function testAcceptBookingStoresTrimmedRemarks(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Open);
+        $booking->setEmail('customer@example.com');
+        $booking->setRemarks('vom Telefonat');
+
+        $service = $this->createServiceWithAccommodation(mailer: $this->createMock(Mailer::class));
+
+        $service->acceptBooking($booking, "  Bitte Zimmer im EG\nund Frühstück um 8  \n");
+
+        self::assertSame("Bitte Zimmer im EG\nund Frühstück um 8", $booking->getRemarks(), 'inner line breaks survive, outer whitespace does not');
+    }
+
+    public function testAcceptBookingClearsRemarksForEmptySubmission(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Open);
+        $booking->setEmail('customer@example.com');
+        $booking->setRemarks('vom Telefonat');
+
+        $service = $this->createServiceWithAccommodation(mailer: $this->createMock(Mailer::class));
+
+        $service->acceptBooking($booking, '   ');
+
+        self::assertNull($booking->getRemarks(), 'an emptied textarea clears the stored remark');
+    }
+
+    public function testAcceptBookingLeavesRemarksUntouchedWithoutSubmission(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Open);
+        $booking->setEmail('customer@example.com');
+        $booking->setRemarks('vom Telefonat');
+
+        $service = $this->createServiceWithAccommodation(mailer: $this->createMock(Mailer::class));
+
+        $service->acceptBooking($booking);
+
+        self::assertSame('vom Telefonat', $booking->getRemarks(), 'the API path must not wipe the remark');
+    }
+
+    public function testAcceptBookingDoesNotStoreRemarksWhenOfferIsNotOpen(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Accepted);
+        $booking->setRemarks('vom Telefonat');
+
+        $service = $this->createServiceWithAccommodation(mailer: $this->createMock(Mailer::class));
+
+        $service->acceptBooking($booking, 'zu spät');
+
+        self::assertSame('vom Telefonat', $booking->getRemarks());
+    }
+
+    public function testAcceptBookingSkipsTheCustomerEmailWhenNoAddressIsStored(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setStatus(AccommodationBookingStatus::Open);
+
+        // Only the office notification goes out — the customer copy has no recipient.
+        $mailer = $this->createMock(Mailer::class);
+        $mailer
+            ->expects(self::once())
+            ->method('createAndSendEmail')
+            ->with(
+                self::anything(),
+                self::callback(static fn (array $options) => 'office@example.com' === $options['to']),
+            );
+
+        $logger = $this->createMock(LoggerInterface::class);
+        $logger
+            ->expects(self::once())
+            ->method('warning')
+            ->with('Failed to send offer accepted customer email', self::anything());
+
+        $service = $this->createServiceWithAccommodation(mailer: $mailer, logger: $logger);
+
+        $service->acceptBooking($booking);
+
+        self::assertSame(AccommodationBookingStatus::Accepted, $booking->getStatus(), 'the acceptance itself must not fail');
+    }
+
     public function testAcceptBookingIsIdempotentAndSendsNoNotifications(): void
     {
         $entityManager = $this->createMock(EntityManagerInterface::class);