Trust comes in the form of being capable and doing the thing that you think is good. You would like to trust yourself to be capable and to be doing what you think is right. You would like to trust others to do things aptly and by your norms, even without your supervision.
Trust in principles will build over time by making mistakes and by successfully applying them. Your trust in a principle is shaky when the principle is new or applied to a new situation. Trust in principles will also be tested on hard and irreversible decisions. This trust is usually proven by checking in with others on your decision and by letting time show you the results.