He doesn't trust people because he knows they are all the same. Everyone cares about their own survival and nothing else, just like him. Since he is more than willing to kill for it, so are they. After all, he has endured through all these years, leading him to be alone, it was the only conclusion that made sense.
It is never easy to endure pain nor uncomfortable situation. It is seems easy to quit to avoid the pain.If you quit you will suffer later. It is far better to endure the pain now and enjoy later. Life is all about endurance.
I am enduring temporary sufferings to fulfill my dearest dreams.