Kuzu no Kamiato

I've lived a serious life for 25 years." So thinks Shino, a resigned office worker. On the worst day of her life, she has a chance encounter with her neighbor, a man who is nothing but a scumbag—the only good things about him being his face and his body. The one thing they have in common is that they live next door to each other, and neither of them knows what "love" is. This is the story of two neighbors who know nothing of love, as they begin to explore it together.

https://www.cmoa.jp/title/358099