By the time he had explained to her why his impressions, though multiplied, still baffled him, it was as if he had been familiarly talking for hours.

They baffled him because Sarah--well, Sarah was deep, deeper than she had ever yet had a chance to show herself.

He didn't say that this was partly the effect of her opening so straight down, as it were, into her mother, and that, given Mrs.Newsome's profundity, the shaft thus sunk might well have a reach; but he wasn't without a resigned apprehension that, at such a rate of confidence between the two women, he was likely soon to be moved to show how already, at moments, it had been for him as if he were dealing directly with Mrs.Newsome.

Sarah, to a certainty, would have begun herself to feel it in him--and this naturally put it in her power to torment him the more.

From the moment she knew he COULD be tormented--! "But WHY can you be ?"--his companion was surprised at his use of the word.
"Because I'm made so--I think of everything." "Ah one must never do that," she smiled.