Can you recommend a contemporary romance novel?

I haven't finished reading the novel. I don't remember the author or the male and female leads. It should have been released before 2003. At the beginning of the novel, the heroine's parents were killed when she was young, and she was adopted by the person who killed her parents. She did not know who the murderer was. The person who adopted her had a son and two twin daughters. Its two daughters didn't like the female lead, so they bullied her all day. They were jealous of the female lead's good hair. One day, they wanted to cut off the female lead's hair, but their brother, who was the male lead, saw them coming home from school in the United States. The male lead didn't like his two younger sisters 'stubbornness, so he scolded them and hoped that they would stop bullying the female lead. He also hoped that the female lead wouldn't have her hair cut off.(Hair was her most precious possession because her mother liked her hair very much. She promised her mother that she would never cut her hair.) That was the first time they had met. Later, the male lead returned to the United States. The person who accepted her was not allowed to play the piano at home, including the twin daughters, but for some reason, she was an exception. Later, he even sent the twin daughters outside (I don't remember where exactly they were sent). The female lead was trained to be an assassin. When she grew up, she met the male lead on a mission in the United States. However, she did not recognize him as the big brother who saved her hair when she was young. Instead, the male lead recognized her from her hair. Because she had interrupted him, he had forced a kiss on her. He knew that she was a little girl he had seen in their house when he was young, so the male lead followed her and found out that she was a famous assassin in the underworld. Angry that his father had trained a weak girl to become an assassin, he returned to Taiwan to question his father…
That's all I can remember. I don't know what the outcome is. That's probably what the novel says.
China, it happened in Taiwan, but they reunited in America

Answer 1

I recommend "Two Little Youguesses" to you. It tells the story of childhood sweethearts. The male and female protagonists used to play together when they were young, but for some reason, they separated. After more than ten years, they reunited in university. One waited bitterly, while the other was like a moth flying into a flame. Can they walk towards happiness in the collision of emotions? I hope you like this fairy's recommendation. Muah ~😗