Trust in God as it was translated at the Mir yeshiva in Brooklyn meant to learn Torah and not to worry about what will come in the future.
Or to be more explicate it meant as a unmarried student just to learn Torah according to the regular four year program at the yeshiva.
The idea was that after one would be married somehow things would work out if one trusts in God.
[The concept of God here is more than the First Cause. It is the First cause that made Nature, but sometimes interacts with the world in a way above Nature. Also there are intermediate realms, like a moral plane that interacts with the world.]
Now according to the view of the Torah, we have two kinds of trust: One of the Duties of the Heart חובות לבבות that is trust with effort. That is to do what is necessary but also to trust that God will make things work out in the way that he wants.
The other kind is of the Gra that one needs no effort and in fact it is better not to do any effort to get things, but to put everything into God's hands. [This idea is attributed to the Ramban also by Israel Salanter.]
[When I saw the Torah being used a means to make money, I got turned off.
But that is just abuse of a high ideal--and a good ideal. People should learn Torah and trust in God. Abusus non tollit usum. Abuse does not cancel use.
Steven Dutch:
Whether religion or unbelief have been sources of good or evil are absolutely irrelevant to anything. The only issue of any significance is whether a position is true. If it's also good, that's a side benefit. I would like nothing better than to find ways around the speed of light and the laws of thermodynamics, but they are still true even if I don't like how they affect things I'd like to do. If something is true but evil, then that's something we have to deal with. Is it at all possible that the Universe was not designed by Walt Disney? Is it possible that our current prejudices ... may be more based on sentimentality than reason?
And another idea from Steven Dutch which I think applies to Judaism: A lot of people will misunderstand the religion and stress trivial issues, ignore or downplay significant ones, or garble concepts. In extreme cases people who disagree with the established religion will attempt to redirect it into a form very different from the original, or take it over entirely. The Gnostics of the early Christian era who cast Persian mystery religions in Christian terms are a good example. Many people will use the religion to rationalize other motives; they will use it as a pretext for prejudice, or dominating others, or lashing out at authority.
Some will adhere to the established religion out of inertia. They feel a need for some kind of spiritual activity, and the established religion is the best (or only) game in town. Some will adhere to the established religion out of fear. They may not really believe in the established religion, but are afraid of misfortune or damnation if they abandon it. Some will adhere to the established religion primarily as a means of securing good fortune, as a security blanket, or as a means of easing guilt feelings. Often they will select elements of the religion for emphasis and ignore other elements.
Many will adhere to the established religion for social acceptance. They may like participating in special occasions, or may value the religion as a symbol of national or group identity. Some will adhere to the established religion for cynical reasons. They may secretly disbelieve everything about the religion but go through the motions for personal advantage, reputation, or social standing or, in really intolerant societies, merely to stay out of trouble.
Once a religion becomes really established, the religion itself can be a route to power, prestige, and privilege. Not only will some people adhere to the religion for cynical reasons, they will become entrenched at its very center.
All the above Professor Dutch says is dishonest. The only honest approaches are these: Some will sincerely believe in the established religion, will critically evaluate its teachings, and will attempt seriously to model their lives on its tenets. Some will decide they do not believe in the religion at all. If the society is reasonably open, they may either become nonreligious or convert to something else. In intolerant societies, they may go through the motions of belief merely to stay out of trouble. Some will reject the religion to the point of revolt and active opposition. Some will adhere to the established religion out of sincere conviction but will disagree with important tenets. They will attempt to recast the religion in more personally palatable terms, or possibly work to redirect the religion itself into more agreeable lines. The changes may be real reforms or merely redefinition into something more palatable.
Appendix: "Trust in God" was a major issue at the Mirrer Yeshiva in Brooklyn. The reason for this in part was that it was a Musar Yeshiva. That means a yeshiva that introduced Ethics (Musar) into part of the daily sessions of learning. "Ethics" here does not mean worldview issue or what is called hashkafa. It means simple books about ethical behaviour. Now part of the reason I think this was important at the Mir is that the students there were not learning Yore Deah for ordination. The entire yeshiva was learning Torah because one is supposed to learn Torah. So people needed a kind of justification for what they were doing.
Later on I noticed that this emphasis on trust in God was much less in other places. Sometimes it was completely absent. But at the Mir it was definitely a part of what was going on and that affected my own worldview since then. [Just to prove my point there was a whole shelf at the yeshiva (in the Musar section) of about 15 volumes of the מדרגת האדם The Sum of Man the book by Joseph Yozel Horwitz. The major theme there is trust in God.
It should be noted that the trust in God at the Mir Yeshiva in NY was in order to learn Torah. That is the idea was you trust in God so that you will not have obstacles towards learning Torah. It is directed towards removing obstacles from learning. The Gra has this in the opposite way. He says the entire purpose of Torah is to come to trust in God.