Trying to find a book I read. It's a romance about a little girl who is kidnapped when she is around 4. I believe her name or nickname is cat. She comes back and her family is rich. Maybe in the hotel business. She sleeps with a man who she believes is her half brother. I think someone is trying to kill her and she falls off a boat ? Any help?

Cat by V.C. Andrews? I don't think that's it, but maybe the storyline will sound familiar.