I'm not sure if it was manga or manhwa. I read it a long time ago, around 2000. Its genres include action, adventure, fantasy. The main character is a boy. He is on his way to school and gets wounded by avoiding a random plant/flower on the street. A random girl, who is able to control plant/flower, sees the whole thing and decides that he will be her prince. She has a sister (could be twin sister), with total different personalities. They share the same power of controlling plant/flower, but with different personalities come different forms of power. I thought it was Origami Warriors, but I was wrong. The story lines and characters are similar. But instead of using origami to present the powers, they use something else (a medal, an emblem...). This is all I can remember as a child, please help if you can. Thanks!!