If you deposit $10k in Wells Fargo you have to trust them for the full $10k. Which you already do by putting $10k in a bank account. If you want to send me you

If you deposit $10k in Wells Fargo you have to trust them for the full $10k. Which you already do by putting $10k in a bank account. If you want to send me your $10k I need to trust Wells Fargo for $10k because I will then have $10k that Wells Fargo owes me. I can then cash it out at say an ATM or branch. Once you have transferred the money to me you no longer need to have the trust and once I cash out I don't either.