Business Magnet's Sweetheart: The Mermaid

Coral was a mermaid from another world. Due to an accident, she was transported into a book, which she didn't even know about until the guardian of the book world informed her. The guardian told her to keep her mermaid identity a secret, but can she keep it? However, can someone explain why the female lead and the male lead son were born villain? Initially, he ignored Coral, but he started becoming possessive upon seeing her with other males. *** "Did you see the way he looked at her? It was like no one else in the room." Alexander always hated it when his mom pressured him to get married or have a girlfriend. But one day, on his birthday, he was given a girl as a surprise gift, and he fell in love with her at first sight unknowingly. But his mom said, "Surprise! I've found a little sister for you, Alexander." "..." *Cute and sweet book*