Urgently Looking for a Quick Transmigration Novel with a Mission to Max Out the Villainous Corruption Level, Then Erase It

The heroine falls in love just before she dies and gets bound to a System. In the first world, she successfully wins over the male lead, then maxes out his corruption value and gets ready to leave after completing her mission. But then the System says she has to lower his corruption value, so the heroine returns to the world after he has turned dark, whether that was years or just hours later.