Romantic movie with a bad boy

Hello, I'm looking for movies with bad boys or where at first the two heroes hate each other but then fall in love. Personally, I really like the series The Mentalist, so if you know any movies with a hero resembling the one from The Mentalist, I would love to see that too. And finally, if you have any other movie suggestions (except horror/gore), please let me know. Thank you in advance.