It seems like she can no longer get out of this.
Ryuuko seems to have everything figured out already. "Your right. I already know Allen has feelings for me."
How long did she know? Lyn was unsure herself, so when Ryuuko nodded and didn't ask, it relieved her.
Her fiance Prince Allen, she thought she could earnestly enter a proper relationship with him. That was why she worked so hard so she could fall in love with him. She deluded herself into the role of a girl falling at first sight for their fiance. She thought if she could be with this man, then her future could change.
"I wanted to break free of my shackles, even if I had to use Allen."
She wanted freedom, even if it meant pretending and lying to herself.
It was wrong of her to do this. What if he genuinely fell for her? It would hurt him in the future when he found out. But she did not have to worry about that. Even when he fell for her, Allen never said a word and continued this game.