Princess Shu

A brief description of the light novel Princess Shu:
Valia was born into a fallen noble family as the daughter of a knight and lived a sad life. Then, the opportunity of a second life comes to her.
‘Should I live like that again?’
No, she won’t!
Valia decides to become a temple princess in order to live a happier life without having to worry about money. But then, as a princess, she becomes the wife of Shuden, the most handsome man and highest-ranking noble in the Empire…!
But in the future, Shuden falls in love with a new woman from another world. Valia knows this, but she can’t get away from Shuden, who is in love with her!
Valia, Shuden’s princess–what is her fate?
“You are the only one in my life that I will love. If I break my oath…I will pay for it with my life.”