He’s used to having the attention of all the women around him, but show him that you’re not falling for that. Call him Romeo or call the women around him his girlfriends.
Show him that you have seen through his act and that you know his sly tactics.
Let him know that he will have to devise another strategy if he wants to make you fall for him because his every move so far is simply not good enough for your standards.
He will be so eager to change your mind, to prove to you that he’s different, that he will become obsessed with you. The trap is set and all you have left is fun and games.