The time when I didn't know anything

[Chinese Drama Cliché☆] Jiyoon leaves behind Sehun, a CEO of a large corporation who only cares about her, and falls in love with Taehyun, a nameless CEO of a company, and they end up getting married. In the end, he is killed by him and the woman he truly loved, and returns to a year ago. At that point, Jiyoon had already spoken rudely to Sehun and was about to marry Taehyun.