Revenge Looks Good in Diamonds

Quick answer: 11 episodes, English original audio, and episodes 1–10 play right here tonight.

Wendy Shaw has just wrapped up a mission in ancient time when the System delivers news that stops her cold. Her best friend Laura Harper has been killed by a man who never deserved her. Wendy takes the new assignment without hesitating. She returns to the 21st century as the true Xavier heiress, steps into a marriage meant for the family's fake daughter, and walks down the aisle to Steve Hart, the scarred eldest son everyone assumes is a punishment posting. Her mission is to make Steve fall for her. Nobody takes Wendy seriously.

The girl from the countryside is supposed to crumble under the Hart family's scrutiny. Instead, Steve's regard for her deepens steadily, and Wendy rises to become general manager of Hart Corp without breaking a sweat. When she finally turns her full attention to Mark Hart, the second son whose hands are stained with Laura's death, everything she has built points in one direction. He never saw her coming. That was always the plan."