His Final Heartbeat, Her Eternal Regret

To resurrect his lover, system asks Adrian Carter to do 100 things for Elena Blake. He finishes 99, but for the last task, Elena demands his heart for her first love. Adrian agrees and dies. Realizing she actually loves him, devastated Elena tries to kill herself but binds with a system. To stay in his world, she must make Adrian say "I love you" within three days. Confident, she enters his world.