For much of the novel, Archer views May as overly sheltered and naïve. It is not until the end of the novel that Archer realizes she has known about him and Ellen all along and is far more perceptive than he ever believed her to be. May’s perceptiveness at the end of the novel is actually foreshadowed about halfway through when she reveals that she is aware of the previous affair Archer had with the married Mrs. Rushworth:

“You mustn’t think that a girl knows as little as her parents imagine. One hears and one notices—one has one’s feelings and ideas. And of course, long before you told me that you cared for me, I’d known that there was some one else you were interested in; every one was talking about it two years ago at Newport. And once I saw you sitting together on the verandah at a dance—and when she came back into the house her face was sad, and I felt sorry for her; I remembered it afterward, when we were engaged.”

Here May tells Archer directly that he “mustn’t think that a girl knows as little as her parents imagine,” a truth that he promptly goes on to forget. But May’s speech here proves her point—she is capable of noticing small details, such as Archer’s unusual physical closeness with Mrs. Rushworth two years ago while sitting outside at a dance, as well as that the woman’s face looked “sad” once she was inside. These are the sorts of details May likely picks up on throughout Archer and Ellen’s emotional affair as well, despite the fact that Archer believes he is successfully keeping his feelings for Ellen a secret.