Once a commoner, Wellmy Ernest ascended to nobility when her mother married an earl. She tormented her same-age half-sister at home and school, stole her heirship and fiancé, and finally sold her off to the allegedly cruel Lord of Magic. It’s not like her plain, meek sister could oppose. Wellmy got everything she wanted. One day, Wellmy receives an invitation to a late-night soiree from the Lord of Magic, likely to announce her sister as his fiancée. Wellmy attends with her mother and father, but what awaits them isn’t the brilliant banquet they were expecting…it’s a tribunal condemning them for their abuse of Wellmy’s sister. Which means everything has gone just as Wellmy planned… This is the story of a lone villainess who plans to make her sister happy even if it means she’s hated in return. *Source: Manga UP! Global*

Having had her engagement broken off and now past the age of marriage, Alerila is known behind her back as the "official lady." She works steadily as the right-hand man to the "cold-hearted Prime Minister," Marquis Easteria Wegmund. One day, while on duty, the Prime Minister proposes to her. Given rumors that the Prime Minister is in love with another woman, Alerila's own low family status, and her status as an unmarried administrative officer, she understands that he is asking her to enter into a contract marriage, and so she accepts the engagement. A businesslike married life with the cold-hearted Prime Minister begins...!! (Source: Comic Earth Star, translated)

Alellia, who has had her engagement broken off, is past the marriageable age, and is known behind her back as the "domineering female supervisor". She spends her days performing her duties as the right hand woman of Marquess Istilia Wegmund, "the cold-hearted prime minister." One day, while performing her duties, the Prime Minister asks her to marry him. Rumor has it that the Prime Minister is in love with another woman. Alellia accepts the engagement, believing that she is being asked to enter into a contractual marriage. A newly-married life with the cold-hearted prime minister begins...! Source: MU

For years, Wellmy Ernest has made her half-sister Iora's life a living nightmare. She forced Iora to obscure her beauty, treated her like a servant, and even stole her fiancé. Their own father and his second wife joined in on the torment, cruelly confiscating Iora's belongings and forcing her to live in a cold, drab detached building. Now that Iora has turned eighteen, Wellmy is ready for the final insult: marrying her off to Aides Ormirage, the handsome yet heartless mage lord. Tonight, at last, her brilliant scheme will reach its climax at the banquet held by Aides himself. Yet as the villainess prepares for her final act, she is acutely aware that all that awaits her is her own doom. (Source: J-Novel Club)

https://www.cmoa.jp/title/291528/ Diora, a perfect lady blessed with exceptional magical power, is caught off guard when her fiancé, Wyles, suddenly announces that he wants to break off their engagement. Even after the initial shock, Wyles stubbornly continues to insist on ending it. Suspecting that he must be hiding a deeper motive, Diora decides to investigate the truth behind his relentless declarations. When she finally uncovers the reality of the situation, his true feelings hidden behind the broken engagement act, is revealed…?! A slapstick romcom featuring a talented, beautiful “perfect” lady and her reckless, foolish prince