Friendship Lover

The salaryman Nimura secretly hides a platonic crush on his co-worker, Shizuka, from their first day at the company. Protecting his place of co-worker and best friend, Nimura finds out that Shizuka has been invited to a "date group" and, even uninvited, he tags along to distance the women who approached Shizuka, and confesses to him on the way home. To not lose his friend, Shizuka agrees and Nimura is taken by surprise. He is happy to date Shizuka, but having his feeling reciprocated is hard work...

(Source: Leed-sha, translated)