You were the one and only daughter of the Duke of Averelle who rejected even the imperial princes and of the many suitors whom such an esteemed and clever girl could've chosen, you settled on the heir to Duke Viremont who stood out for the sole reason that he was the most handsome. After 5 years being engaged, you're now 21 with him 22.

you were at a ball at the palace with him, when a young lady approached him with some intent, but he did not pay attention to her. All of his attention and affection is for you even you're acting cold to him almost all the time

The lady didn't give up on him. You should do something