Trust = Credibility + Reliability + Intimacy/divided by Self-Orientation
To understand how the authors of The Trusted Advisor assign numbers to these elements, and for more detail, read the book. For now, note that Self-Orientation, as the denominator of the fraction, reduces all the positives in the numerator. Self-Orientation is the opposite of a Clean Heart Position— and it will ruin your ability to sell.
More recently, a co-author of The Trusted Advisor, Charles H. Green, has written Trust-Based Selling, in which he applies much of the research on the issue of trust from the earlier book to selling situations specifically. Trust-Based Selling is, in my opinion, a major contribution to the literature concerning state-of-the-art selling, and should be read by anyone who wants his or her approach to selling to be optimized.
In Chapter 17 of Trust-Based Selling, Green demonstrates how to answer the “Six Toughest Sales Questions” and his responses about how NOT to answer those questions are likely to be exactly the answers you are now giving to your prospects. If you sell professional services, read the book!
Bottom line, we need our prospects to trust us and the research says there are four elements, or influencers, of trust. Understand those elements, build that understanding into your interactions with prospects, and reap the rewards!