You become trustworthy one returned hoodie at a time.

Trust is not declared, it gets assembled out of small returns. The hoodie given back, the charger returned, the money repaid without being asked twice, each one so minor that nobody comments, all of them counted anyway. That is why somebody can be sincerely sorry and still not be trusted, while somebody unremarkable quietly gets handed the keys.

Return whatever you are currently holding that belongs to somebody else. Today, without waiting to be asked. That is the whole mechanism, repeated for years.