Courage and Competence
Honesty. Integrity. Courage. Competence. Benevolence.
Combine those and it is likely that you have a thoroughly trustworthy individual.
The two qualities that may be missing from many lists are Courage and Competence.
Courage is needed to put the other virtues into action.
Competence is also needed for action and it is a key ingredient of reliability. A person who possesses Honesty, Integrity, Courage, and Benevolence won't be able to fulfill the necessary commitments unless Competence is present.
All are needed to create Trust.