Good idea to write a book! PLEASE?

I have some ideas i just don't like them that much so please give me insight on what you would love to read. Give me a plot with romance for sure, probably fantasy with fairies, witches or mermaids. NO VAMPIRE OR WEREWOLVES! PLEASE! just tell me what you'd like to read and give me and idea of an awesome story, I would also like something sad in there, to teach you how to deal with stuff