Trust, whether it is trusting yourself or trusting others, is important in today’s world. If there was more trust amongst each other, there would be less conflict, which would also lead to less of a need for self defence.
Firstly, you must always trust your own instincts. Understand right from wrong and act accordingly. When you do act, follow through until the end, especially if you say you are going to do something. Your word is your bond.
Trust needs to be a two way street. If you can be relied upon to do the right thing, it makes you dependable. But, this can also work the opposite way. It takes a long time to build up real trust, but it can be lost very quickly. Therefore, you must continue to do the right thing.
Speaking of which, if somebody does not do something you agree with, you must learn to forgive. It is hard to do the right thing all of the time. This does not mean the other person is untrustworthy. They may have just made a mistake. A true martial artist learns to move forward, which in itself engenders trust and respect. These are important tenets to leading a peaceful life.