What is the ruling on a woman taking commission from the owner of a utensils shop in exchange for guaranteeing his customers' payment of installment prices for goods?

The commission for a guarantee (ḍamān) is prohibited according to the four schools of thought, and a consensus (ijmāʿ) has been narrated on this matter. This is because taking a fee for a guarantee leads to a loan that draws a benefit, and there is no difference in the prohibition whether the one paying the compensation is the guaranteed party (the debtor) or the beneficiary of the guarantee (the creditor).