How we change what others think, feel, believe and do
Be honest. When you are asked a question, tell the truth. Tell the whole truth, not an edited version that avoids key facts.
If telling the truth may harm another person or where the truth would be betraying confidence, rather than just lying, explain that you are unable to answer. Do not name people who may be harmed by saying this.
Avoid lying just to get yourself out of trouble or where you know that this would be wrong. In particular avoid lies that get you what you want at the expense of other people.
If you know things that you believe the other person would want to know, tell them rather than waiting to be asked.
If you have done something wrong, own up and apologize. Do not wait to be asked. Just confess, then try to make things right for the other person.
Yes, It was me. I chopped down the apple tree.
I thought you'd want to know that there has been a problem in the area recently with crime. The police say they are looking into it but maybe you should drive rather than walk.
I'm sorry, I forgot to buy you a birthday present. No excuses. I apologize. Can I take you out to dinner?
When asked questions we often think carefully before replying, usually as we do not want to be disadvantaged or harmed by our answer. Selfishness is at the core of distrust, and so trustworthiness has to show unselfishness and a concern for truth over self-preservation.
If you tell a truth that clearly disadvantages you then this will sharply increase the trust you get in return. The beat way to do this is to tell truths and expose vulnerabilities that are not to your advantage but are not that harmful either. What tips the balance for you is the additional credibility you gain.
So when might you not tell the truth? If the truth is too difficult to tell, then an honest answer is to say just this. Worst case you can change the subject or otherwise avoid answering. Truth may also be avoided if other people would be harmed by telling the truth. This is not always easy as many would still prefer the truth over a white lie.