She is not sure of him

Quite delightful!" cried Mrs. Clay, not daring, however, to turn her eyes towards Anne. "Exactly like father and son! Dear Miss Elliot, may I not say father and son?"

"Oh! I lay no embargo on anybody's words. If you will have such ideas! But, upon my word, I am scarcely sensible of his attentions being beyond those of other men."

I always thought this a quite telling sentence as it seems to imply that Elizabeth is aware of how a gentleman would behave if he was interested in her, and she sees it not in Mr Elliot. Surely then she must know that Anne is receiving such attention ?