Goei Kareshi no Uraomote

Feared for her prestigious family name, she lives a lonely school life—until a sudden engagement demand leaves her stunned. Just then, a charming young man steps in, claiming to be her boyfriend. In reality, he’s her assigned bodyguard, protecting her from fiancé candidates with ulterior motives. To avoid suspicion, they must pretend to be a lovey-dovey couple at school. Sweet in public, teasing in private, and secretly falling for her—his act may not be just an act after all…!? A high-energy reversible romantic comedy where fake love turns real! (Source: Pixiv Comic, translated)