Gokutsuma Days: Gokudou Sankyoudai ni Semararetemasu

Self-proclaimed otaku and shut-in Sakura Kisaragi would prefer to spend her days alone in her room, playing her favorite yakuza-themed dating simulator. But when she saves the life of an old man who turns out to be the head of the Amou-gumi crime family, she inadvertently earns a spot in the yakuza's succession plans—moved by her courage, the old man declares that whoever among his three ambitious grandsons can win her hand in marriage will be the next boss. Now kind but ailing Shuusuke, brash hothead Reo, and cool and calculating Ryuusei are all vying to make her their boss wife—but will she be anything more to them than a means to an end? Meanwhile, not everyone in the Amou-gumi organization is happy to have her there...

(Source: Kodansha USA)

Included one-shots:
Volume 11: Uranai to 0 no Kimi., Hoshimotogurashi