Ya'll I need help. It's a korean manhwa where they were both children at the start of the story but the girl who has black hair is actually someone who remembers her pastlife and the boy who she became friends with fell in love with her. They soon die from an accident and reincarnate as opposite genders, the black haired girl becomes a guy and the brown haired boy becomes a girl. And the brown haired boy remembers her from the last life.
The cowardly tiger is so cute