It's not that girls like assholes, its that they like confident, masculine guys. Assholes just tend to have these qualities more often than nice guys. Think about it, what are some characteristics of femininity? Emotional, caring, sensitive. Sounds a lot like the charactistics of nice guys. You don't have to become an asshole to get girls, just remember your evolutionary role as a man and maybe be a little more confident and don't let her see you cry when bambi gets shot.