Please help with title.
This girl was one of the many girls chosen to be potential bride for a young king.
Her entourage left her at the gate, as they were only allowed to go so far. Through the dark tunnel leading from gate to palace she befriended a 'girl'. Unbeknownst to her that was the teenage king himself. She became close friend with the king's older sister. There was political unrest. People were trying to dethrone him. I think at the end they died in each other's arms.

It was really romantic how their friendship grew... n gradually she learnt of his real identity as none of other potential brides really met him.

Greatly appreciated if anyone could name that anime.

Additional info- it was early 90s Anime.