GISOU KEKKON SHITA RIVAL NI DOUYARA 10-NEN MAE KARA AISARETE ITARASHII

"I'll teach your body everything I've learned in the last 10 years—" Wakabayashi Yu, an elite police superintendent on the career track, decides to enter into a fake marriage with her colleague Mikoshiba in order to get promoted. Mikoshiba is just a colleague and rival. That's what she thought, but she never imagined that things would turn out like this from the very first day of living together—!? (Source: Kodansha, translated) — Description from AniList community (anilist.co).