A true friend is a friend you have trusted for many, many years, and they didn't ever betray your trust. Not even once. It's the best definition I can give.

A true friend is a one in whom you have placed your trust for many, many years who did not even once disappoint that trust. It's the best definition I can give.

A true friend is a friend you have trusted in for many, many years, and who has never betrayed your trust, not even once. It's the best definition I can give.