In the matter of reforming things, as distinct from deforming them, there is one plain and simple principle; a principle which will probably be called a paradox. There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, “I don’t see the use of this; let us clear it away.” To which the more intelligent type of reformer will do well to answer: “If you don’t see the use of it, I certainly won’t let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it.”
In this sense, trust is a polarizing strategy, and it's one that is important to apply early on in the relationship before someone becomes important to you. If you trust someone excessively and it goes badly, but they don't matter to you, you can just kick them to the curb. In general, trusting someone at a level that seems slightly excessive for their level of importance to you will help you sort people in your life who you want to be more important to you than they are from those who you want to be less important than they are.
And it does need to be excessive. It needs to be trust beyond reason. Not beyond all reason, but somewhat beyond what currently seems reasonable. If it is not, then unless they are prepared to take the first move, you will never find the signs you need to move to a higher level of mutual trust.
Sometimes this will go badly, but you need to be able to try bad things.