Why does Hale say that he recognizes Rebecca even though they have never met?

Rebecca Nurse has already arrived at Reverend Parris's house when John Hale, the famed witch-hunter, comes at Parris's behest. When Hale first notices Rebecca's presence, he asks,

You cannot be Rebecca Nurse? . . . It's strange how I knew you, but I suppose you look as such a good soul should. We have all heard of your great charities in Beverly.

In the stage direction, when Rebecca first arrives in the scene, Miller tells readers that "Gentleness exudes from her." Moreover, he writes that "the general opinion of her character was so high" that it defies reason to imagine how anyone could accuse or believe her to be a witch. Therefore, it seems that Mr. Hale is able to recognize Nurse because there is something about her person—an aura, possibly—that seems to mark her as especially good and holy. Her mere touch even has a calming effect on Betty Parris, one of the sick little girls who the community fears has been bewitched. Hale has already heard of her as a result of her righteous and upright reputation, and so he recognizes her based on what he has heard of her and his own observations of her person.