You develop trust by how you conduct yourself, how you react and deal with situations. The primary reason salespersons are effective is not in their popularity or grasp of product knowledge but in their ability to be trusted by their customers, according to a recent USA Today newspaper survey. They want to help you succeed. It's important to have technical expertise, but without integrity that knowledge means little. A sense of humanity and sensitivity toward others.
People respond to and enjoy being around persons who are passionate about their work.
That promotes believability. Consistency in temperament that allows room for flexibility. They want to know what to expect. Willingness to take risks. Have faith in yourself and in your convictions.