Dekiai Seiyaku: Ijiwaru na Kare no Aishi Kata

Rio is terrible at romance and always gets dumped whenever she dates someone. One day, she happens to stop by a bar and unexpectedly runs into her boss, Hozumi.

At work, Hozumi is gentle and soothing, but in private, his tone and attitude are completely different. Confused, Rio is surprised when a casual remark she makes leads to him suddenly kissing her. "I'll teach you. The joy of being loved." After being sweetly and forcefully pursued, the two somehow end up dating with marriage in mind...!?

(Source: Funguild, translated)