Tanzawa Yuu

A lady who's bad with romance begins a rehabilitative romance with a younger rental boyfriend. Yukari was traumatized by her relationship from when she was in university and she has come to avoid romance ever since. When she heard that her ex will be attending their upcoming class reunion, she unintentionally promised to bring along her boyfriend despite not even having one. In her panic, she decided to "rent" a boyfriend, and the rental boyfriend who appeared on that day was a handsome and hard-to-grasp, younger guy... source: https://www.mangaupdates.com/series/m4qsm5n/honki-de-shitemo-ii-desu-ka

\[from Behind The Smut:] "I don't intend to treat this as a one-night stand. I'll take responsibility, and make you happy for the rest of your life…!" Shirakawa Anzu, 26 years old. She's serious and not good at relying on others, so she has her hands full in both love and work… When she finally gets dumped by her boyfriend, she gets drunk and has a one-night stand with her boss, but he's called a "modern-day samurai" and a stubborn man! The next day, he feels responsible for her, and declares that he'll make her happy forever…?! Some loves start on their knees! A slightly-mature love story between a samurai boss and a heart-broken girl that goes against the usual progression of love!