Princess Varvara speaks to Dolly in a very patronizing, condescending manner; she happily condones Anna and Vronsky’s relationship. Dolly recognizes that Princess Varvara doesn’t care what Anna and Vronsky are doing so long as she is able to reap the material benefits; Dolly, on the other hand, loves Anna in spite of her choices. Vronsky shows Dolly around a hospital he is building; he is happy to show it off to someone new and gets excited.
Princess Varvara is kind to Anna and Vronsky only in order to keep taking advantage of them, and Dolly sees right through her simpering ways. On the other hand, Dolly can see why everyone has fallen in love with Vronsky, as he is quite charming when he gets animated about the hospital project—she herself cannot help falling under his spell.