My "radar" has been disappointed in the past; however, in my opinion, trust is generated over time and tested by consistency, demonstrated adherence to principle, and candor. If one cannot be consistent and reliable in small things, we cannot expect reliability on larger issues. A fellow I knew as a sales representative for our employer changed his opinions or background to better relate to an intended customer, and I thought that a bit odd. He was a good salesman, a revenue generator, but his integrity was as plastic as his credit cards. Another who boasted of his own integrity seemed to have difficulty remembering his marriage vows on business trips.
We observe acquaintances or coworkers who make commitments and fail to live up to them, appointments that are easily forgotten, claims that are meaningless, and we have to wonder about the merit of their word.
The deeds have to match the words. If a person claims to be thorough or meticulous in issues requiring attention to detail but cuts corners in key areas for his own convenience, that inconsistency is telling. Another claims to honor the confidence or trust of others but betrays that in gossip. Can you expect any more of this person?
An individual makes a mistake or miscalculation and refuses to report or admit it...worse, implies another is responsible for it. That person is not be trusted. A person claims to be motivated by altruism and concern for others but treats the server badly in a restaurant. There is a dissonance or inconsistency here.
These examples and others are not issues that are immediately evident; they are demonstrated over time. We are required, for our own protection, to exercise discernment. Trust is generated in small increments, in matters of increasing importance over time. We are dealing with human nature, and our world is filled with great variety. People of integrity exist, but many more are incapable of meeting the tests of time in business or in friendship. Our challenge is to observe patiently and weigh the evidences objectively.