Well I don't know how to read minds yet, but I think it's good to give others the benefit of a doubt. Try to ignore the gossip though, you can be sure that those people only care about themselves if all they do is talk bad about others.

You could try talking to this guy you like, (not that that's an easy thing to do ) And maybe he'll still dissapoint you, but people aren't perfect, and if they care about you they will try to do better from now on.

Your trust is something that others have to earn, the gossipers obviously are untrustworthy, but has the guy done anything to lose your trust?