I have my close family and friends that I trust. Now, there are some things that I do not trust each person with for various reasons, and no one besides my husband that I would literally trust with anything/any info about myself. Like, I won't discuss religion with my mom and some other family members; we disagree too much and it is a waste of time on both sides. And even my best friend, there are lines I draw regarding trust as well.
There were times that I could actually not trust my self.. times that I did bad things that put me in danger. So I do not think that oneself can always be trusted more than another person!
In business and selling things: I never, ever front anything to anyone. They pay me first or it is a no-go. Had a guy years back who wanted to buy an item from me that had to be shipped. He made a small payment and then wanted me to ship the item. Nope. Turns out, he had some excuse about not being able to afford the rest of the item's cost anyway; I would have been out the item and the $$.