How we cite our quotes:
Under all her saucy satire, provoked chiefly by her divination that her friends thought of him as a desirable match for her, [Gwendolen] felt something very far from indifference as to the impression she would make on [Grandcourt]. (10.32)
Gwendolen usually feels like she's not just in control of herself, but everyone else around her, too. It's interesting, then, to see how startled she is when she worries about the kind of impression that she'll make on Grandcourt.
Gwendolen found a relief for herself by thus changing the situation: not that the tête-à-tête was quite disagreeable to her; but while it lasted she apparently could not get rid of the unwonted flush in her cheeks and the sense of surprise which made her feel less mistress of herself than usual. And this Mr. Grandcourt, who seemed to feel his own importance more than he did hers—a sort of unreasonableness that few of us can tolerate—must not take for granted that he was of great moment to her, or that because others speculated on him as a desirable match she held herself altogether at his beck. (11.37)
Grandcourt seems to take away Gwendolen's sense of power over situations, even when they first meet and she thinks she's still sassy and in control. She feels "less mistress of herself than usual," meaning that she doesn't feel like her usual shot-caller self.
"Will you do me the honour—the next—or another quadrille?"
"I should have been very happy," said Gwendolen, looking at her card, "but I am engaged for the next to Mr. Clintock.—and I perceive that I am doomed for every quadrille: I have not one to dispose of." She was not sorry to punish Mr. Grandcourt's tardiness, yet at the same time she would have liked to dance with him. She gave him a charming smile as she looked up to deliver her answer, and he stood still looking down at her with no smile at all. (11.86-87)
Here we see Gwendolen trying to manipulate Grandcourt. She's totally playing games with him, and we can see that it's sort of working.