“ Self-distrust is the cause of most of our failures. In the assurance of strength, there is strength, and they are the weakest, however strong, who have no faith in themselves or their own powers. ”
— Christian Bovée
Distrust was a common theme in LOST. Throughout the series, it was a common refrain, "Trust me," especially when one character was trying to get another character to agree to their position, mission or action.
Self-distrust is an interesting sidebar to this discussion. If one cannot trust herself or himself, then how can that person trust another person? In real life, the biggest trust factor is in a committed relationship like marriage. If one cannot trust one's spouse to be loyal, then the bonds between them are weak. But if one cannot trust one's self to be loyal in that relationship, there is added anxiety and stress - - - even if the other spouse is not at fault.
There were a few characters who had no faith in themselves. They could not call any inner reserve to change the course of their life. Desmond was a person who could not trust his decision making process or even his instincts, especially with his relationships with women. He calls off his engagement to join the military as a means of avoiding a commitment. But when Penny rejects him, instead of trusting himself to win her back, Desmond goes off on a crazy mission to impress her father, Widmore, instead of working on his personal relationship with Penny. He ran away instead of trusting his own feelings and strengths in order to win back Penny.
Hurley was another character who could not trust himself. He could not trust himself in relationships with women. His shyness and abandonment issues led him to cower in asking a girl out on a date. When his best friend wound up with his first crush, then put Hurley into a distrustful hermit mode. His continued depression which started with his father's abandonment led him to body imagine issues. Like Desmond, he ran away from his problems, but instead of a suicidal boat race, Hurley took to food. On the island, he could not trust himself to be the pantry keeper. He could not fathom rationing food when he craved the the very thing he was meant to protect.
Sawyer had a distrust of everyone. Growing up as a loner, he made sure he could only count on himself. He did not trust even his partners in crime. When he let down his guard, his partners took advantage of him with disastrous results. But Sawyer distrusted himself in regard to his own personal relationships. He saw people he met as "marks" and not friends or potential lovers (until he time traveled and became close with Juliet.) Sawyer somehow distrusted the "normalcy" that a normal relationship would have on his psyche, which was solely devoted to revenge for his parents death.
In Sawyer's case, when he began to "care" (in his own way) for his fellow castaways (when Jack, Kate and Locke were gone), this opened the door to care about other people . . . to open up to become involved in a real, adult, committed relationship.
In Hurley's case, he had to be literally dragged off the edge of insanity by Libby in order to learn that non-family could love him for himself and not for his money.
In Desmond's case, he never proved to himself that he trusted himself to be with Penny. It was blind luck that it was Penny's boat that rescued him when the island disappeared (and the O6 was created to deceive the world). Penny's will had more to do with Desmond returning to her than anything Dez did. Further, Desmond did not trust his own inner strength because he kept himself and Penny away from them - - - hiding from the ridicule that Widmore would heap upon him for being a coward. Desmond's weakness that he would not be accepted by powerful people kept him in a state of confusion and on the run for his entire life.