Hinata ni Rin to Saku Himawari-sou

The story focuses on Harou, living his life as a husband. On a rainy day he loses his wife in an accident. With a broken heart he returns to the pension where his wife lived to take care of the sunflowers he loved so much. But it will not be easy since the manager hates him and blames him for killing his sister, yet for some reason, he still hires him.

(Source: Sword Demon)