Consider her suggestion

Truth be told, both sisters are voluptuous with more than adequate looks. Sure, Lisandra, your father's mistress is objectively more beautiful, but they are younger. Plus, they look inexperienced with men. Taking your silence as a permission to continue, Dobra tell you about them.

Shara, the elder sister was trained by her father as a warrior. While adequately proficient in fighting, she instead focuses on archery, knowing very well that her strength couldn't match someone properly trained. You guess that's the reason your men managed to capture her without any casualty as she couldn't get away far and fast enough to shoot down them; she was busy trying to prevent her family from being captured. Sure, an admirable trait but you don't really care for such chivalry since her father wasn't a shining example of one either.

Dobra tries to portray Misha, the younger sister, as an intelligent girl. You're not really sure about that since there's no proof but there's evidence that she's more stacked than her tomboy sister. Besides, from what you can see, she's less likely to kill you in your sleep, which is a big plus in your opinion.

Well, Dobra's suggestion seems appealing. You wanted to be a gentleman but the mother is offering her daughters for your enjoyment. It is foolish to reject the offer, or isn't it?