I had a breakthrough recently on this very topic. I was struggling with a wavering trust (could also call it hope) and was trying to understand just what makes it waver. I had eaten some meat (at a restaurant!) that was slightly smelly in a not nice way, which I unfortunately only noticed after swallowing some of it and was struggling with the fears it triggered in me. Especially since I ended up researching about food poisoning.
Anyway, I was close to unable to concentrate on anything much and my intuition kept telling me that there must be a way to view the situation that doesn't practically paralyze me with fear. Eventually it dawned on me that the problem was that I was collating two different kinds of trust together that don't need to be linked. One of them was the trust that I'd be fine, which rationally speaking, couldn't be guaranteed in that situation and the other one turned out to be the trust that I could accept myself and the world.
The problem was that I was refusing to accept the world (and thus myself) where I'd get sick (with the potential for severe problems if unlucky) from eating that meat. Yet, the rational part of myself kept insisting that it's a potential outcome, which ended up using most of my mental resources in the conflict.
Once I realized that, I was able to accept the possibility and thus the internal conflict dissipated. The refusal to accept was kind of a circular construct in that it was itself somehow the argument for not accepting. As in I can't accept it because it'll lead to me not accepting it which I is too horrible to accept.
Anyway, what I want to say here, is that the rational arguments are probably not the problem here but rather that you can't accept yourself and/or the world if what you're afraid of comes to pass. So, the key, for me, was that I don't need to trust in the future. I just need to trust that I will accept myself and the world, whatever it is that comes at me.
P.S. I did get some very slight stomach problems a few days after the event, but it's unclear whether they were caused by the meat or just the stress from the fear.