We never trust anyone; you only trust your judgment about that person. So when someone lets you down, it’s easier to think – that someone did you wrong, rather than the reality, which is that you have lousy judgment. The mirror is hard to look into.
If you work or live with someone who produces a negative feeling in you, the first step to get beyond (above) this is to acknowledge that that negative feeling arises out of you. It is a feeling produced inside yourself, not the other person.
And nobody ever rejects you; they are only rejecting what they think you are. But that cuts both ways. Nobody ever totally accepts you either.