I absolutely do "not trust really anyone" because everyone I could even be in a position of trusting has either betrayed that trust or preemptively acted in a way that shows that they'd take advantage of that trust if I were foolish enough to trust them. Every human being I've encountered has acted in a way that shows demonstrably that trusting them is a mistake.

Furthermore, studying psychology, sociology, and anthropology has shown me why. Human beings are hard-wired to exploit those people not in their social groups in order to help those people in their social groups. Every human being in a group acts (in a successful, functioning tribe) as a conduit or processor of resources from outside the group. In a world where most resources are no longer "wild", that necessarily means exploiting outsiders to secure and protect the insiders. Which is great for those inside a social group, as that social group will tend to protect an individual member from other social groups. But if one has no social group, one is "fair game" to everyone - the outcast has no protection outside of their own fangs and claws, and he or she finds themselves surrounded by spears.

To the outcast, trust is merely the conman's tool - a method of exploitation used to extract resources from the outcast that doesn't involve open violence.

MedusaX and ShaneG have the right idea; it's not a person's responsibility to trust people unconditionally - people have to behave in a trustworthy manner to get that trust. But instead, I have found that people would rather exercise power over others to force that trust, to use force to put people in positions of disadvantage instead of being trustworthy.

But one can't assume such a person exists. There's not a physical law forcing the creation of such a person, and one cannot depend on random chance to supply one.

It's in everyone's best economic interest to not reciprocate with anyone not already in their social circle.

Then the only reason to deal with people is if you're put under duress to deal with them. If they cannot be depended on, then the cost of dealing with them is guaranteed to outstrip any gain you may get from them.

People have, as a rule, expected and demanded perfection from me - and are willing to use any amount of violence to enforce it. Stating that it's "unrealistic" to expect the same thing from others as they demand under pain of violence of me creates a clear conflict; an inherent imbalance of power ripe for exploitation. And people demands of my perfection cannot be stopped - they'd literally face any other fate rather than lessen their demands.

It doesn't matter if you have "strict" boundaries or not - people will violate those boundaries no matter how "strict" you may be about them, simply to demonstrate that they have the power to do so. In fact, many people see strict boundaries as a personal attack - asserting that there are things they cannot do is seen as a personal attack on their liberty, as if you're invading their territory - violating their boundaries - and stealing from them.

I have never been a pushover in my life, but my boundaries have at best been considered nonexistent because people do not consider me human enough to have valid boundaries - to them, it makes as much sense to respect my boundaries as it does to "respect" the "boundaries" of a coffee table. And any attempt that I make to enforce my boundaries is interpreted as an unwarranted attack precisely because no one can conceptualize the fact that I'm a human being that can have valid boundaries. Any "consequences" I show for violating my boundaries don't get psychologically connected to violating those boundaries because people refuse to conceptualize my own agency; people insist under duress of any consequences that I am an object, capable of being owned and therefore cannot have its own boundaries separate of its owner.

One can "teach" people how to trust us, but it cannot be expect that they are interested in learning - and in fact it economically behooves them not to , as obeying those boundaries represents added cost for reduced gain.