Kitty and Vronsky dance several waltzes together, and Kitty turns down five invitations for the final mazurka, the most important dance at the ball, because she is waiting for Vronsky to ask her. Kitty sees Anna and Vronsky dance together, and Anna looks triumphant. Kitty perceives that Anna has achieved the conquest of one man, not simply the admiration of many.
Kitty has shown her feelings to Vronsky, but he does not return her advances, and instead of choosing her for the most important dance, he has chosen Anna. Kitty’s ill-advised choice has caused her to turn away other eligible suitors. Vronsky has fallen in love with Anna, not Kitty.
When the final mazurka arrives, Kitty has no partner; at the last moment, she is saved from being a wallflower, but the evening is ruined. Kitty is crushed and broods on the interaction between Anna and Vronsky. Instead of admiring Anna wholeheartedly, Kitty now sees something threatening in her.
Kitty used to idolize Anna, just as the Oblonsky children do. However, now that she sees Anna as a rival, she perceives something threatening, alien, and not altogether wholesome about Anna's enchanting qualities.