It's an interesting problem. What would it take to create in oneself a state of trust and when would it be useful? We are all well aware that it is risky to trust other people, and we are also aware, when we pause for a moment, that many important aspects of our life rest on our ability to trust. Often, we need to consider a situation from many different points of view (and hearing and feeling) before we can find the limits within which it is appropriate to trust or to be trusted.
Tonight I sent my university-student son an exercise in noticing when he is prepared and applying that state to studying for a particular exam. Whether or not he does the whole exercise or enters into the pretending it suggests, just reading through the exercise will suggest to him that he has known how to be prepared and can have access to that knowledge now. It will affirm that he trust himself as he prepares for his exam.
None of us face tests (whether or not they are academic) unless we trust ourselves. Whatever trust means (and it is a slippery word), it begins with making a connection between what we experience and what we believe to be true. Without that trust, we cannot engage in greater trusts: the trust in principles or in God depends on our ability to trust ourselves at least enough to stabilize this one element of our experience.
If we accept that we know how we experience trust, then we can begin to chunk that experience into its sensory components and to replicate them, either by will or by association. Obviously, this is a risky enterprise, since we may teach ourselves to trust in situations where trust is not justified. It is a risk we have to take if we are to be doers rather than thinkers, an act of ego that paradoxically enables us to trust others and to influence them, too.
Too often we accept that trust, like other emotions, is a natural program that unfolds despite our best efforts. It may be true some of the time. It is not the only way of thinking about trust.