Oblonsky arrives with a proposal

Oblonsky, fresh from buying oysters at Eliseyev's, meets Betsy in the doorway, kisses her hand above the glove where the pulse beats, and learns that the whole town is talking: Anna is fading away, and either Vronsky must take her off or Karenin must divorce her. He has come to Petersburg partly for that and partly to thank the Court for making him Chamberlain. Anna he finds in tears. She has heard that women love men for their faults; she hates her husband for his virtues, cannot live with him, is driven beside herself by the very look of him, and knows she is not worth his little finger. She is a tightly-strung cord that must break, and twice reaches for the word death before her brother cuts her off. His almond-oil smile calms her while he sets out the case — married without love to a man twenty years older, in love with another, forgiven — and arrives at divorce. She shakes her cropped head, and her face lights with its old beauty, because it looks to her like an impossible happiness.

Tolstoy sets Oblonsky's shallowness to work as genuine kindness, and the almond-oil smile soothes because it is not pretending to understand. Anna's admission that she hates her husband for his generosity is the exact cost of the forgiveness he was so glad of. The refusal she gives is not a refusal; her face has already answered.