Konyaku Haki Shita Aite ga Mainichi Shazai ni Kimasu ga, Fukuen Nante Zettai ni Ariemasen!

Her fiancé, who is infatuated with the daughter who claims to be the reincarnation of a saint, tells her that he is breaking off the engagement. Duchess Sarah, exhausted by her relationship with her fiancé, accepts. Her furious parents sent her to a convent, but she was relieved to finally be able to live a quiet life. Just when she thought that peaceful days would return, her ex-fiancé appeared at the monastery and apologized to her. There is no way they will ever get back together, even if he says so now!

(Source: Kodansha, translated)