18+ Fake Wife

In order to save her ill father, Yoo Yeonwoo makes a dangerous deal to deceive the members of the esteemed Taeseong Group. Her task is to pretend to be her estranged twin sister, who disappeared just before her marriage to Taeseong's youngest son, Cha Kitae. Yeonwoo only needs to keep up the act for six months, but in the fifth month, she is found out at the worst time possible: right after refusing to get intimate with her sister's man. When asked for forgiveness, Kitae offers her a simple solution. "Just make it up to me with your body, Yeonwoo."

(Source: Tappytoon)