Reijou Elizabeth no Kareinaru Migawari Seikatsu

Elizabeth Magnus, from a minor noble family facing financial difficulties, is kidnapped by a man she does not know. The man is Duke Sylvestor, who mistakenly believes she is his missing sister, also named Elizabeth. After realizing the error, he proposes a deal: she will impersonate his sister for six months or until he locates the real one, in exchange for financial assistance for her family. Elizabeth agrees, beginning her life as Elizabeth O’Brien, the supposed daughter of a noble family.