......taking Ain out of the equation? ..... hmmmmmm.......... nope! Sorry. I lost my interest. I like you and all, but what brought me to you was your son. Take him out, and I never would have approached you. Give it time.
He just wants to make sure if roselia's feelings for the duke and ain is the same or different!
Roselia said she's interested to the duke as his wife, but it's so ambigous, the duke consider a chance that roselia is only interested to taking care of him like she does to ain, but the duke is not a child, he's her husband, so he expect an interest between a man and a woman since they're obviously marriage couple, that's why she should consider her interest to the duke without thinking about ain
She shouldn't have lied. If she had just told the truth, even though she thought she might not look as great in his eyes, he probably would have liked her. If she had honestly said: It was Marie. Then he would have had a favorable impression of her