Trust is etymologically related to true which refers to validity. Trusting another has to do with whether they are truthful in thought, word and deed. Though a person may have honorable and genuine intentions in a moment, intentions change. Trust is based on action, not intention; it is a response to actions and experience in present conditions.
My belief in Sweetheart is about his skills and abilities based on experience. I believe he can because he has. Trust is similarly based on history, but it is about emotions and feelings rather than acquired skills. Trust refers to relationships, how a person treats and respects others. There is also a competence form of Trust, but this is more of a belief, a person may believe in the quality of a person's skills to perform a specific action, but believing a person will perform that action is a matter of trust. In relationships, Belief is about can and Trust is about will. Believe that someday your MLCer will do what he can; that he will act within his abilities to be a good person and at that time offer your Trust. Trust is about present actions and if your MLCer's present behaviors are not trustworthy it is not your spousal duty to give them your Trust.