Both are mini dramas in which identical FLs of different personalities swap places in a contract marriage to a rich CEO after the original fiancée runs off/disappears shortly before the wedding. The ML ends up falling for the replacement bride.
Both dramas involve the FL pretending to be someone she looks exactly alike (twin sister vs. a stranger), leading to a relationship between her and the ML.
Both are mini dramas in which identical twin sisters with very different personalities are forced to trade places by their parent/parents, leading to one marrying and falling love with her sister's rich fiancée.