Kojirase Yakuza wa Osananajimi

The introverted Kanae Toyama was about to be forced to sell her body to pay for her family's business debts, when she was saved by a yakuza gang member. The yakuza turned out to be her childhood friend Michiru Matsunaga. In order to pay off the debt, Kanae ended up working as a live-in housekeeper at Michiru's place.

(Source: Comic Days, translated)