Akuyaku Reijou wa Single Mother ni Narimashita Futago wo Hikitorimashitaga Koushaku-sama Kara no Dekiai wa Souteigai desu

Without realizing that she had been reincarnated as a villainous lady, Duchess Estelle's engagement to the Crown Prince was broken off. She decided to live a modest life as a commoner from now on, and decided to work at a restaurant in a neighboring country. Six years later, she was running the restaurant while raising the late owner's twin daughters, Coco and Mia, but... Duke Frederick, who claims to be the twins' older brother, visits her, and she ends up pretending to be his lover to protect the twins from being embroiled in an inheritance dispute! A romantic fantasy about a fake engagement between a villainous lady who is at the mercy of a cold-hearted duke, unaware that she has been reincarnated into a game ♡ (Source: Ichijinsha, translated)