Yakuza Fiancé: Raise wa Tanin ga Ii

Somei Renji is Somei Yoshino’s grandfather and leader of the “Somei Group”, the Kansai region’s biggest yakuza group. When he arranges for her to be married to Miyama Kirishima, Yoshino has to move to “Miyama Clan” estate, the Kanto region’s biggest yakuza group. Kirishima warmly welcomes Yoshino and is such a pleasant, personable, and nice young man that nobody would suspect that he comes from a yakuza family. This puts Yoshino at ease even though she was initially feeling insecure in this unfamiliar place.

But then, a certain event leads to Yoshino witnessing the real Kirishima.

(Source: Crunchyroll)