I used to feel the same when I was younger, had a lot of "friends" who would steal things, manipulate me and use me for my stuff and then throw me away.
I felt at that point that I couldn't trust anyone with just about anything in my life. I shut myself off from everything and kept to myself.
As I started to meet people who were genuine about me, I kinda started to trust people again. I'm now at the point where I believe I have every reason to trust someone until they give me a reason not to.
Trying to believe humans aren't inherently evil and don't only look out for numero uno. Can be a bit of a funny thing and sometimes I don't even believe it myself.
If the whole world is your enemy, how are you ever meant to make friends? How are you meant to progress or succeed in whatever it is you want to do?
You NEED friends to get where you need to go. Or at the very least, you need connections or associates. Which means at the very least you need to be on good terms.
Give and take, that's how relationships work, and that's how friendships work.
Sometimes you have to give something to a friend, time out of your day to listen to a hardship, labor if they're moving houses or they bought a new piece of furniture or a TV, sometimes you even need to lend a friend some money if they're in a bit of a bad place financially.
These are all things we have that we can offer, but equally they're all things others can offer us. In a friendship we can give without expecting anything in return and vice versa.
So I can see where both sides are coming from, I can see how you could not trust anyone, see everyone with a dagger behind their back.. Ready to betray you.
Equally though, I can see that while every may have that dagger behind their back, not all of them intend on stabbing you with it.