Zettai Ni Ma Work [top]: Secret Mission Sennyuu Sousakan Wa

The guard coughed.

“Then I arrest you tomorrow.”

Ren Akasaka is the top investigator for the Metropolitan Security Bureau. Known for his "ice doll" persona, he never fails a mission. His new assignment? Go undercover as a personal assistant to the CEO of a suspicious tech conglomerate, Misaki Toujou, to uncover evidence of illegal data trading. secret mission sennyuu sousakan wa zettai ni ma work

If "ma work" = "night work" (夜の仕事), then it's an erotic thriller. But given your phrasing, I doubt it. The guard coughed

He laughed—a real laugh, surprised and bright. “You’re terrible at being fake, you know that? Your smile doesn’t reach your eyes when you lie. On day three, I knew you weren’t a real waitress. By day seven, I knew you were an investigator.” I knew you were an investigator.”