Kagehime no Konrei

Kagehime no Konrei summary:

Izuna has been living the life of a double, devoting it to represent Princess Kisara of the East country, who has always had a very weak health. Even within the East country, a very few within the Royal Palace knew about Izuna's real identity. And the only one who called Izuna by her real name was the real princess.

Izuna's time of serving as Princess Kisara's double was supposed to come to an end once it was decided that Princess Kisara would be marrying to the Crown Prince of the West country to bring peace between the two countries. However, just a few weeks before the marriage ceremony, Princess Kisara's health suddenly turned worse. The Princess realized she had failed to set Izuna free of serving a life of a double. She apologized repeatedly at her deathbed, leaving the two countries' peace on Izuna's hand.

Now Izuna will probably have to lead the rest of her life as Princess Kisara, marrying a person from the enemy country. She vowed to fulfill her precious Princess's dying wish. However, she vowed never to fall in love with her future husband.

But, what exactly awaits Izuna in the West country?