1. Being forgiving should have limits. I agree with the others above that this MC is one of many who definitely cross the boundary between forgiveness and outright naivete.
2. This "barter" power is extremely powerful. From i checked back in chapter 1 or 2, she can steal anything from someone with just a few vague words as long as there is mention of an exchange. No need to make it clear what is actually being traded. No need to trade things off equal value. You can even imply that something else is being traded than your actual target and don't need to mention the actual target at all. That's not "barter", that's outright scamming.