Let me put it in extremely simple terms then.
Trust isn't perfect. A person can do something that puts you off. Not enough to break trust*. Just wobble it some. "Hmm," Jane says. "That seems...off."
She goes to DM Alice. "Alice, you did a thing that concerned me a little." How does Alice respond?
Per this thread, Alice responds, "You just have to trust me." No answers. No accountability. No work to build trust. No work to keep trust. Trust MUST be there, flawless, from time zero. Just, "You must trust me."
To me? That answer writes off Jane's mild worry in a very worrying way. Far from calming a wobble, that answer IS breaking trust.
*People get so mad at me for "extreme" positions attributed or taken...and then they do this. Seriously, you yourself have just MADE this two hard, binary extremes: either trust is utterly full and complete and perfect without even the slightest hint of a whisper of a shadow of a doubt, or it has thoroughly and utterly failed. There can be no in-between for you, no shades of grey. Either trust is utter and perfect and you'd never question anything a DM did ever, or you cannot ever believe anything at all and completely reject any association whatsoever. How is that not a ridiculously extreme stance?
I haven't tried to make this anything. I've told you how I and my group operates. Something about the way I've done that does not sit well with you, but I'm not really sure why. You seem to be asking me for tips on dealing with limited or broken trust, but I have no answers for you. As I have already explained, I don't think I'm the best person for to be looking to for help on that topic, because I don't really experience the problems you're talking about.
I honestly don't know what else to say. The issues that arise around the gaming table are, in my experience, trivial. How we resolve the imaginary outcomes of imaginary quests is simply not worth getting angry and upset over. It's not worth allowing doubts and concerns to linger and fester. I am not friends with people who love to cause drama (or, if I am, they're smart enough to keep their drama out of my sphere), and I rarely deal with drama and angst in my life. If one of my players does have a problem with something I do, they will just tell me, probably bluntly. I will listen and give their concerns honest contemplation. If I then say (with respect to a game-related/GM judgement call concern), "There's a really good reason for that, just trust me," then they will almost certainly trust me. One of the reasons they trust me is because they know that I can take feedback on board and if I've made a bad call, I'll almost certainly recognise it and make amends. And, if occasionally, we just continue to disagree, we'll talk it out a bit more but, ultimately, if we don't reach a consensus, they'll defer to my judgement because I've been running games for them for over 20 years, they like the way I run them, they know that I'm never making a ruling just to be a mean or because I'm on a power trip and if very occasionally I make a call they don't like, it's just not that big a deal. They know that someone has to have the power to make the final decision and, in our group, that's the GM.
In the last game I was a player, the GM railroaded us at one point. How do I know? It felt like it at the time, but later he straight up admitted it, with no prompting. I didn't like it at the time, but it was just a game, he hasn't run games in ages, he was stepping up to give me a break and it wasn't worth worrying about. When it felt clear to me we only had one choice at the time during the session, i rolled with it, rather than causing the game to break down.
If that campaign was going to continue for a lot longer, I would have let him know I didn't like it, explained why and we would have had a discussion about it. If he wanted to keep running games like that, because it made it easier for him, I would probably have got on board and just lived with it for a while. Maybe he would have made efforts to change the way he runs? Who knows. Either way, it's just a non issue. And, like I said, since it was only quite a short term thing, and it only happened once, I didn't even feel the need to bring it up. And it didn't damage my trust in him, or willingness to play along,
at all.
I have a player who has a good friend (some one he is probably closer to than me) who has been pestering him for a long time to join his D&D group. This player chooses not to, because he doesn't have enough time for two regular groups and he wants the sort of games I tend to run. He likes knowing the world doesn't exist for his character, but that his character, if he plays well, can bend the world to his will. He enjoys many of the things that some people in this thread believe are impossible or illusory. And he trusts me to give him those things.
I don't know what else to say. That's my experience. Those are my thoughts. Make of them what you will. I am genuinely sorry if my position or the way I explain it upsets you, makes you feel angry, makes you feel as if I'm not reading what you write or as if I'm dismissing the way you feel. That is not my intent.