What is the issue of trust as it pertains to the merchant, his wife, and Sir Don John?

At the end, when the Host concludes that the monk tricked both the merchant and his wife, he seems not to have realized the victor at the very end of the tale. Rather like in the Miller’s and the Franklin’s Tales, we are asked to consider each of the participants at the very close of the tale, and decide who we think has come off best. It is clearly not the merchant, though he has made huge profits in his business dealings, and had his loan repaid, and, though (as the Host argues) the monk has had sex with the wife, remained friends with the merchant, and got off scot-free, it is the wife herself who seems to triumph. Not only has she had enjoyable sex with both the merchant and the monk, but she is one hundred franks better off; and she coerces her husband into agreeing to “pay” in return for sleeping with her.