How to reject a guy nicely?

there is this guy in my dance class, and he really likes me is quite obvious and my freinds think he likes me too. but I really don't like him, I can't even see him as a freind. I don't know there is just nothing no feelings of affection of any kind at any level for this guy. I mean I think he's very nice and all which is why I wouldn't won't to hurt him when I let him down. so how do you reject someone in a way that gets the point across but doesn't completely sound horrible?