At the beginning I thought trust was based on results: when you give, on a consistent base, something valuable to someone, you gain some trust.
I don’t say this is wrong and my experience says that in most cases this is not enough (and sometimes – unfortunately? – not so required). To gain trust, you must create a deep relationship with the other person: if he perceives you as part of the same “tribe”, you are worthy of trust.
Of course this relationship has to be based on facts, results, behaviors but … the other person is by far more tolerant (and see more values) in someone that delivers a bit less but with which he has a STRONG relationship than with someone that has an outstanding score but POOR relationship.