In love with my best friend... help!?

So my best friend is this guy I've known since 6th grade but I never really hung out until last summer. We really got to know each other and everyone told me that he liked me but I always denied it. But now I think I like him, too, and I don't know what to do about it... And I can't just walk up and tell him, because I'm not so sure if he likes me anymore... Can somebody help me figure out what to do, at least like maybe a discreet way to tell him? I really think I love him but I don't know how he would react... and I really don't want to ruin our friendship, because it means SO much to me. Thanks in advance!