Oblonsky's wife, Dolly, is with one of her sons, Grisha, when Anna comes in.
Although she told her husband that she didn't care about Anna's arrival, Dolly remembers that Anna is, in fact, a big deal because her husband Karenin is one of the most important people in Petersburg. As a result, Dolly prepares carefully for Anna's arrival.
Dolly is willing to give Anna a try: she wants to tell Anna everything. But she's also angry and humiliated that she wants to talk about Oblonsky's cheating heart with his sister.
Anna comes into the room, and Dolly tries to figure out if she knows about their situation (i.e., Oblonsky's affair with the governess). Dolly concludes that Anna does in fact know.
Anna asks Dolly after all the children, remembering their names, ages, and everything about them. She greets Tanya, Dolly's daughter, when she comes running in and then running out.
Dolly expresses envy for Anna's vitality.
Finally, the two of them sit down for coffee.
Anna gets down to business, and Dolly's coldly resentful, because she expects Anna to repeat the clichés everyone's told Dolly already.
Anna doesn't do that, though. Anna says that she doesn't want to defend her brother or console Dolly, but that she's sorry "from the bottom of [her] heart" for Dolly.
Then, she asks for Dolly's version of events.
It turns out that Dolly thought it impossible that Stiva would ever be unfaithful.
She points out that all her good looks were taken away by her husband and children.
Dolly is especially horrified by the idea that her husband and his mistress discussed her.
Anna finds this impossible because for men of Stiva's position, their home and their wives are sacred territory, not to be mixed with their mistresses.
Anna succeeds in convincing Dolly to forgive Stiva by asking if there is enough love left in her heart. And she points out that Stiva still loves and respects Dolly. Dolly asks if he'll do it again, and Anna assures her that he won't.
Dolly asks Anna if she could forgive adultery, and Anna says that she would forgive in such a way that she could go on as though it hadn't happened at all. Dolly agrees that, if you forgive, it must be completely.
Dolly is much more relaxed and thanks Anna for coming.