How do you reject someone you might have lead on?

Well, I've been in your shoes, and I can definitely say from personal experience that it is possible to be friends with a guy that liked you and asked you out. In fact, a guy exactly like that (who had a crush on me for 4 years and asked me out 6 times) is one of my best friends. So don't discount the fact that it is possible to be friends with him. If I were you, I just wouldn't do anything unless he actually asks you out or tells you that he likes you. It sounds like he's a shier guy, so he probably won't do that unless you really really encourage him to. My advice: just back off a little. In time, he'll realize that you aren't into him, and it will be fine. The biggest thing right now is not to make a big deal out of it. If anything, just pretend not to notice that he likes you. If he does ask you out, pretend like its not a big deal. Don't get awkward and flustered, just tell him that you don't feel the same way. The next day, if you see him at school, act exactly like it never happened and he'll act the same way. No harm done. Good luck! Hope this helped!