To trust is to place one's confidence in someone or something. Trust implies a belief in the truth of what one is told or promised. It suggests a willingness to place one's faith in another while having no guarantee of a positive outcome.
With trust comes uncertainty. The more confident we are that a person or entity will fulfill his/her/its commitment the more willing we are to trust him/her/it. Still, we can never predict what will happen in the future with complete certainty; thus, there is always some degree of uncertainty associated with trust. For this reason, we talk about trust in terms of probability. When deciding to trust (or not to trust), we try to assess the most likely outcome(s) of the situation at hand.
So how do we know who (or what) to trust? This is a question with important consequences. If we place trust in the wrong people, we end up getting manipulated, used, or taken advantage of. If we refuse to trust anyone, we become paranoid and suspicious and we deprive oursleves of meaningful and fulfilling relationships with others.
Unfortunately, there is no magic formula that allows us to make a calculated decision about who we can trust. There are, however, a few basic guidelines that I have found helpful.
1. Trust is not an allor nothing concept. Many of us assume that either we can trust a person or we can't; there is no middle ground. If we can't trust a person completely then we can't trust him at all. This mindset can create a lot of unncessary problems. It can cause us to place unconditional trust in the wrong people or to prematurely terminate meaningful relationships in response to even the smallest violation of trust. It is more helpful to think of trust as varying by category and degree. From this perspective, you can decide to trust someone in one area but not in another. For example, I might trust a friend to pick me up from the airport on time but have absolutely no trust in her ability to keep a secret. We can still have a perfectly healthy relationship; I just know not to tell her anything I don't want anyone else to know.
2. It is best to trust a person only as much as you know him. Some of us have the tendency to get ahead of ourselves. We meet someone new; by the end of the week we've told him our entire life story. Having just met this person, we have no idea how he will react to or what he will do with this information; we have no information upon which to form an opinion. Sometimes I talk to my patients about red flags. For example: if someone you've known for less than a month asks to borrow money, your car, or some other significant item - RUN! This is a red flag!
3. The best predictor of what a person will do in the future is what you have seen him or her do in the past. There are, of course, exceptions to this rule. People can and do change. It is, however, rare that they do so spontaneously; there is almost always a precipitating factor. Change requires long term commitment. Rarely do people invest the time and effort to change unless the negative consequences of their behavior start to pile up. Some examples. If a friend is always late and has given no indication that she is committed to changing this behavior, you can trust that she will be late the next time you invite her somewhere (no matter how important the occasion). If a family member has a history of lying, you can trust that he'll most likely lie to you at some point in the future. It is in your best interest, then, to investigate whatever he or she tells you before accepting it as truth. If your spouse has consistently demonstrated that he or she is bad with money, you can trust that he or she will probably continue to make poor financial decisions in the future. It would be quite foolish to trust him/her to manage the family's finances; such trust would have no basis in reality.
4. If a person is determined to deceive you he will probably succeed. Let's face it: there are people out there who lie, cheat, steal, and manipulate. Some people are so good at deception that even the most discerning among us are fooled. Fortunately, the majority of people are not con artists. Over the course of a lifetime, almost everyone will be betrayed or deceived at least once. It is never a pleasant experience. While it is natural to want to avoid such pain in the future, deciding never to trust anyone ever again is not the best way to do it.