The Prince and Lily

https://www.cmoa.jp/title/335072/
Lily has spent years enduring exploitation by her relatives while struggling to protect her ailing father. When the royal palace discovers that her embroidery carries a mysterious blessing, she is offered money in exchange for transferring that power to Prince Zenon through an intimate ritual. Lily accepts, expecting a purely contractual relationship that will end after their first night together. But Zenon does not act as she expects, and their hesitant life together gradually turns into something much more emotional. As Lily realizes her growing feelings for the prince, she also learns that the blessing is essential to his claim to the throne. Their arrangement becomes a tender, tension-filled romance in which a planned farewell may turn into lasting love.