Positively Yours
Vice president and a schoolteacher have a one night stand she becomes pregnant and he proposes marriage
Remarried Empress
Empress is living a peaceful life until the Emperor falls in love with a runaway slave and makes her a concubine
I Became the Hero's Mom
Female lead dies and jumps into her favorite book, becoming the mother of the story's hero
The Office Blind Date
Best friend convinces the ML to go on a blind date in her place turns out to be the director from her company. She dates him with a hidden identity... then he discovers who she really is and he's convinced on marrying her.
Nindan - Danshikou de Ninshin Shita Ore
Omae no Tame ni Houritsu Kaetakara, Ore to Kekkon Shitekure
His childhood friend changes the law so that he can marry him.
La Dolce Vita di Adelaide
Pretends to be engaged to the Duke so he doesn't have to get married to a "Saint". Them pretending turns very real they confess their feelings for eachother but first they have to prove all the crimes the Saint has done so they can get married.
I Didn't Mean to Seduce the Male Lead
After spending the night with the Duke. He now wants to marry her but their social status is getting in the way
Why are you doing this, my Duke!? Webtoon