But it was only, only, because I didn't know--and you must admit that you gave me scarce reason enough.

Reason enough, I mean, to keep clear of my mistake; to which I confess, for which I'll do exquisite penance, which you can help me now, I too beautifully feel, to get completely over." That was what, while she watched herself, she potentially heard him bring out; and while she carried to an end another day, another sequence and yet another of their hours together, without his producing it, she felt herself occupied with him beyond even the intensity of surrender.
She was keeping her head, for a reason, for a cause; and the labour of this detachment, with the labour of her keeping the pitch of it down, held them together in the steel hoop of an intimacy compared with which artless passion would have been but a beating of the air.

Her greatest danger, or at least her greatest motive for care, was the obsession of the thought that, if he actually did suspect, the fruit of his attention to her couldn't help being a sense of the growth of her importance.
Taking the measure, with him, as she had taken it with her father, of the prescribed reach of her hypocrisy, she saw how it would have to stretch even to her seeking to prove that she was NOT, all the same, important.

A single touch from him--oh, she should know it in case of its coming!--any brush of his hand, of his lips, of his voice, inspired by recognition of her probable interest as distinct from pity for her virtual gloom, would hand her over to him bound hand and foot.

Therefore to be free, to be free to act, other than abjectly, for her father, she must conceal from him the validity that, like a microscopic insect pushing a grain of sand, she was taking on even for herself.