Konyakusha no Uwaki Genba wo Michatta node Hajimari no Kane ga Narimashita the Comic

The future looks bleak for Sophelia von Lotus. The behavior of her arranged fiancé, the crown prince, leaves much to be desired, and her family makes her feel like a stranger in her own home. Even so, she is committed to her duties as the future crown princess, enduring hardship and humiliation alike for the good of the kingdom. That is, until Sophelia catches her husband-to-be in a compromising position with her younger sister! Seeing her chance to escape the miserable future awaiting her, Sophelia screams to alert everyone to her fiancé's indiscretion, and help comes running in the shape of Sir Livionis, a dashing knight (and longtime secret admirer) who urges her to run away with him. Abandoning the only life she has ever known, Sophelia takes his hand and tumbles into a heartstopping romance and a completely new life. But what awaits this young couple as a new love rings?

(Source: J-Novel Club)