The Cold Truth Behind the Sweet Trap / Beyond the dark abyss / Entwined Abyss / Pseudo sibling trope

She thought he loved her. Their love was forbidden. He was a stepbrother, but I’ll turn out was a lie. He was just using her for revenge. He thought that her mother killed his mother, and he wanted to make her fall in love with him, then dump her when she found out about it she was brokenhearted and she decided to go abroad, but she did not want him to know. She quietly left, and he realize he had fell in love with her, but it was too late. she decided to move on with our life and find someone that was worthy of her love.