Tears of the Palace

The ending is a bad ending, so please steer clear if that bothers you!

She was a princess of a fallen kingdom.

He had once been held hostage in her lands.

He killed her fiancé with a single arrow.

She hated him with all her heart.

After he brought her back to his homeland, she plotted day and night to kill him.

He gave her all his favor and tenderness, waiting for her to respond. In return, she drugged him again and again...

By the time she uncovered the truth about what had happened back then, he had already been poisoned too deeply...