Synopsis
Is It Wrong To Seek The Happiness Someone Else Denied You?
Sara, a royal maid in the Kingdom of Saleilles, is ordered by the king to enter a political marriage with the eldest prince of their rival kingdom, Ferrier—but as the body-double of the real princess! But then Sara’s boyfriend cheats on her with the princess she considered a friend and turns on Sara completely! Utterly betrayed by those she trusted most, Sara hits rock bottom, heart shattered…
Farewell, Princess I used to love and respect. Farewell, my once-beloved boyfriend.
So Sara makes a decision—she will find happiness in Ferrier no matter what! But that all hinges on her husband-to-be…a reclusive, misanthropic prince who has a slightly difficult personality and is constantly wearing a mask. To make matters worse, rumors are spreading in Ferrier of a terrifying black beast on the prowl…
Can Sara ever hope to find happiness in these conditions?!
LN information (.epub)(official) 
Genre: Drama, Fantasy, Mystery, Romance, Shoujo, Supernatural
Volume 01 or (Mirror)
Completed
Password: thatnovelcorner.com
Thanks for sharing this! The synopsis makes this sounds like similar other light novels with the beast being the love interest…