Protective adaptations (even if they are harmful in outside situations) serve a purpose in the environments they developed in.
Sometimes "learning to trust" in the abstract can cause more harm than good by encouraging people to ignore instincts that are functional and protective.
This means that advice given or presumptions made may not be at all applicable.
All living things have them.
They are responsible for keeping us safe and alive.
They should be respected as such, even when they are problematic or need to be recalibrated.
"This is unpleasant, but maybe it's really necessary for them"
This doesn't mean you can't be hurt or distressed by them, but it can help to understand them better.