She sometimes asked herself what Henrietta Stackpole would say to her thinking so much of this perverted product of their common soil, and had a conviction that it would be severely judged.

Henrietta would not at all subscribe to Madame Merle; for reasons she could not have defined this truth came home to the girl.

On the other hand she was equally sure that, should the occasion offer, her new friend would strike off some happy view of her old: Madame Merle was too humorous, too observant, not to do justice to Henrietta, and on becoming acquainted with her would probably give the measure of a tact which Miss Stackpole couldn't hope to emulate.

She appeared to have in her experience a touchstone for everything, and somewhere in the capacious pocket of her genial memory she would find the key to Henrietta's value.
"That's the great thing," Isabel solemnly pondered; "that's the supreme good fortune: to be in a better position for appreciating people than they are for appreciating you." And she added that such, when one considered it, was simply the essence of the aristocratic situation.
In this light, if in none other, one should aim at the aristocratic situation.
I may not count over all the links in the chain which led Isabel to think of Madame Merle's situation as aristocratic--a view of it never expressed in any reference made to it by that lady herself.

She had known great things and great people, but she had never played a great part.