Seijin Koushaku-sama ga Last Boss da to Iu Koto wo Watashi dake ga Shitteiru: Tensei Akujo wa Hametsu Kaihi wo Mosaku Chuu

Grace, the daughter of a minor noble family, realizes just before her debut in high society that she has reincarnated as the villainess of a novel she read in her previous life. In the story, she bullies the heroine and meets her downfall alongside her husband, Liam. However, the truth behind it all was that Grace had been manipulated by Liam, who later became the final boss. Determined to avoid her doomed fate, Grace struggles to distance herself from Liam—but instead, she only manages to pique his interest, somehow ending up engaged to him!? To make matters worse, her secret—being unable to use magic—is exposed, pushing her into an even more precarious position. At this rate, she’s headed straight for destruction again…! As Grace resists Liam and fights against fate itself in an attempt to change the future— what will await her in the end…? Source: MU