Trust is an astonishing thing. Think of relationships of all kinds–siblings, parents, spouses, friends, the relationship we have with our bosses or employees, and even the reliance we have on government agencies, on teachers, police, doctors—and our expectations of drivers in traffic. All of these and countless other relationships are based on trust. The plaintive words of Blanche Dubois, “I have always depended on the kindness of strangers” are not the character’s alone. We are all Blanche DuBois. Trust is the lubricant without which life would be impossible. We have to believe, to trust, that the sun will rise each day.

The birth of trust in ourselves is the beginning of a healthy ego. We can be children without trust in ourselves, but we cannot be functioning adults without it. That is why the words of our Lord are difficult for adults: “Unless you become as a little child, you cannot enter into the Kingdom.” We must have the vulnerability of a child whose trust in his father’s love is so complete that he can be tossed in the air, knowing his father will catch him. Once a self-governing ego is formed, that kind of trust is very hard to learn.

But humans are weak and can’t bear the burden of trust. We betray those who trust us, just as we ourselves are betrayed. This may be the hardest lesson of maturation, discovering the frailty of those we depend on and our own weaknesses as well. Sometimes a betrayal of our trust can be too devastating even to imagine. A woman I used to know refused to know about her husband’s philandering: “Whatever else George may have done, I know he’s never been unfaithful to me.” George had made passes at half the women in that town, including me, his wife’s best friend. His philandering was his reaction to the burden of her trust, but in the end, he gave in to that responsibility. They remained married until his death. He never confessed to her. I knew her very well, well enough to know that her trust was her weapon to preserve her marriage. It worked.

About ten or twelve years ago, a young friend, a former student, was attracted to two men and knew she had to choose between them. “Pretend you’re going to marry one of them,” I said. “How does the future look to you with each of them?” The prospect with one was excitement; with the other, security. “Now recognize that one of them will be your children’s father.” The marriage is a very happy one, blessed with four children so far. She told me she didn’t fall in love with her husband until she became pregnant with their first child. The other choice is now single, after two divorces.

The least trustworthy person is the one who says Trust me. To demand trust is to demand someone’s reliance, which is power. Trustworthy people never demand trust. Having no desire for power, they have no need or reason to make such a demand. People trust them because they’ve proven worthy of it, not because they demand it.

We all disappoint people. We let them down. We wound by our betrayals, just as we ourselves are wounded. And then we forgive—because we have to. Why forgiveness is given is no real mystery: We have to forgive because life is impossible without trust. But how to forgive is another question. Contrition makes it possible, but in the absence of contrition, we must forgive as Christ did from the cross: “ … for they know not what they do.” It is the only way to continue loving someone who has betrayed our trust. If he had not forgiven us, the world would have ended. Literally. It is not an overstatement to say that forgiveness makes it possible for all of creation to endure. We know by experience that it makes it possible for our souls to endure. We can’t survive the wound of betrayal without it. Not just the betrayals of those we love, but a priest, a spiritual director—anyone we believed in, anyone in whom we trusted.

In old age, we find that unrealized dreams or disappointed hopes are, in the end, quite bearable. It’s the sorrows that endure, and all our sorrows are repetitions of that incurable wound that began in Eden, the betrayal of trust, a word that means faith.