One Piece: I am Imu - Chapter 252: A World on Fire

Witnessing her boyfriend cheating on her with her bestie, Shiyao was so angry that she went to a pub for fun and met a man, who was really a piece of work. After a crazy night she fled away, but was embarrassed to know that the man she slept with was her boss You Ze.
Jesus, give her a break!

- Description from Novelupdates

An unrighteous and a cold hearted man. a villain who struggled from the bottom to the top of society. to overcome his foes he chose to be ruthless and immoral.In a world full of cruelty Jon Hardy had no intention to hold back.A story of a man who traveled back to 1945 equipped with his knowledge of the future and his profound wisdom, Jon Hardy is determined to pursue his ultimate goal once again.

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

I became an extra who confessed to the main character in a female-oriented romance novel but was rejected – an embarrassing history. However, I tried to brush it off as no big deal, until… “…Didn’t you say you liked me?” After you rejected me, why are you now clinging to me…?