I have suffered a personal setback. Someone I considered a friend has proved false. The details don't matter. They are the usual sad melange of self-interest and broken promises. For me, the real issue is trust. I am angry with myself for trusting someone who, with hindsight, was obviously a wrong 'un. I will find it hard to trust again. However, I know that if I allow my misjudgment to inhibit me from trusting, that will damage my life. No trust, no friendship. No trust, no cooperation. No trust, no business.
Attitudes to trust underly politics too. For example, it's not that Socialists trust the collective because they are more trusting. Quite the contrary, in fact. They can see clearly that, left to their own devices, many - if not most - individuals will fail to follow socialist principles. If the massive twentieth century experiment in Socialism proved anything, it proved that. They therefore consciously use State power to enforce their principles "for the greater good". Christians may mutter sadly that "if only" everyone would live a Christian life, the world would be a better place. Socialists are more proactive.
Some Conservatives trust State power too. They want the same big gun as the Socialists, but they want to point it in a different direction. They can be identified by their Daily Mail warcry of "It's a disgrace!" when some wrongdoer escapes the righteous vengeance of the collective. Such people are no more attractive to me than the statists of the left.
Libertarians - or "classical liberals" - trust individuals, but not because we are naive. We don't trust them, for example, to act in a distinterested way. We predict that, more often than not, they will act in accordance with their own perceived self interest. Sometimes we can seem rather cynical because of this. Sometimes Left and Right will attack us for approving of - or even encouraging - the negative aspects of human nature. I don't think that's so. We approve of benevolence. We approve of philanthropy. We are just realistic. We believe that if the State's interference is minimal; mainly focussed on arbitration between conflicting self interests, it can achieve maximum benefit for minimum involvement.
In a sense, therefore, I could trust my ex-friend. He perceived his self-interest to require that I be betrayed. So he betrayed me. Were I a better libertarian, and a worse friend, I might have predicted that.