Trust, as we like to think of it, is a fundamentally flawed notion. Much like love, we take a family of similar but still different emotions and tendencies and label them as a single thing.
"I trust you with my life," is a nearly meaningless statement. The fact is that most people, rightly so, have faith in the basic goodness of individuals.
Let's say that I was to suspend myself from a block and tackle above a forest of razor sharp spikes. Let's also say that I did this in the middle or Times' Square on a busy Saturday. Let's also say that you are the one holding the other end of the rope and that it is only your grip that keeps me from falling to my impalement. I'm confident that you could grab virtually any passer-by in the metropolis of New York City and then, after showing them my predicament, force the rope into their hand and they would not drop me. Insomuch as this, I am willing to trust any stranger on the street with my life.
This example is melodramatic in the extreme but the fact remains, virtually any sane person, when put into a clear cut situation of 'do X right now or Y person will die before your eyes' will act, at huge inconvenience and even danger to themself, to preserve the life of stranger Y.
Put more succinctly, there are many more people that I will trust with my life than I will trust with my wallet.