Kekkon Yoteibi

Already Yoshiko Kawai's life was not going the way she had planned it, but when her boyfriend breaks up with her a few days before her 29th birthday she is at an all time low. She bumps into her handsome coworker Yuki and confides in him that she's worried about not being able to get married before she turns 30. "In that case, if you don't find a partner in the next year, how about we get married?" Initially Yoshiko brushes his proposal off as a joke, but could it be that he is actually being serious?

(Source: MangaPlaza)