Sennen no Hanayome

Chitose is the youngest daughter of the Totsuki clan, known for their vast lineage. Blessed with good looks and spiritual energy, she receives an unending string of marriage proposals. When her older sister, Kuon, lays a trap for her, Chitose is left cursed and transformed into an old woman. Although Chitose always loved children and hoped to become a mother someday, her dreams have been dashed, and she must spend her days suffering Kuon’s abuse, which she bravely endures… until a mysterious man named Kotaro appears before her and declares that he will grant her wish!

(Source: Kodansha)