Iyashi no Otonarisan ni wa Himitsu ga Aru

Fujiko is a serious, hardworking, yet ordinary, office worker. She is insecure about not receiving a post-secondary education, but despite this, she worked hard and became a permanent employee at an insurance company. However, she spent her days unable to refuse any work given to her, accepting it all with a smile on her face. One day, a new neighbor named Nishina moved into the apartment next to hers—an incredibly handsome man and an elite-level office worker. He is also a very kind gentleman, and bit by bit, Fujiko begins to feel comforted by spending time with him. She wonders why he moved into such a run-down apartment building, and why he is so kind to her. Nishina doesn't give her many answers, but it seems there's more to the story than what he's revealing...

(Source: Amutus)