Credibility and trustworthiness go hand in hand. To gain credibility you must do what you say you will do . Make sure not to commit to doing, fixing or taking care of things that are out of your control or capability to handle. If you are honest and side with under promising and then you over deliver, you will see your credibility and trustworthiness rise with those around you or those that work for you. As for me, I am blunt and forward, but I lead from the heart more than the head...and this works for me. I am known as being a problem solver and for making things happen, because I don't commit to doing something out of my span of control or ability to make happen. Over time you become known for what you can do because of what you have done, and this leads to credibility and trustworthiness which is crucial to leading. It works for leading others at work, leading your family, and sometimes even leading your friends. Be credible and trustworthy and model the way for others. After all, it's the right thing to do.