this is my solution now:
.h
DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam(FOnGotQuest, FQuestItem, QuestBook);
UCLASS(ClassGroup = (Custom), BlueprintType ,meta = (BlueprintSpawnableComponent))
class PROJECTX_API UQuestBook : public UActorComponent
{
GENERATED_BODY()
public:
.......
UFUNCTION(BlueprintCallable, Category = QuestBookFunctions)
void AddQuest(FQuestItem questItem);
UPROPERTY(BlueprintAssignable, Category = CharakterProperties)
FOnGotQuest GotQuest;
...........
.cpp
void UQuestBook::AddQuest(FQuestItem questItem)
{
QuestItems.Add(questItem);
GotQuest.Broadcast(questItem);
}
this is the blueprint binding (looks a little bit strange)