Seduced by My Proud Fiance Ep. 1

On the day the Stone family's second daughter is to be married, the long-dead eldest daughter returns, now inhabited by Ellie, a thousand-year-old immortal. Sent to repay a love debt, Ellie is bound to Sebastian, a cold and powerful heir who resents her across lifetimes. As she restores the fallen Stone clan and earns his love, Ellie finally breaks her love trial only to give up immortality to save him.