Best way, fix him up with one of your cute friends. Keep telling him you like him as a friend and its never going to happen, while she flirts it up with him, and hopefully they hit it off. Problem solved.
You need to be CLEAR. Tell him you want to be FRIENDS and you only like him that way. If he stops being friends with you over it he never saw you as a friend to begin with and it's his loss. Did I mention that you need to be CLEAR?
Fart a lot around him. Tell him you're a feminist. Tell him you can't get enough of black cock. Tell him you think kissing means you're engaged. Ask him what he thinks about going down on a girl with a bad yeast infection. Always leave your tampons in view. Tell him what you want to date an old man beciase you just want money. Take him shopping all day with you.