Jessel along with the governess when they were at the pond. Flora looked directly at the spot where Ms. Jessel was supposedly standing and didn't seem surprised when the governess mentioned she was there. When the governess spoke with the ghosts, she learned of Peter Quint's strange relationship with Miles. There is no way that she would have known of this. She obviously could not have imagined that correct information in her head. .
Though the governess came to Bly generally sound, the ghosts of Peter Quint and Ms. Jessel soon became her obsession and seemed to drive her to insanity. Her original intentions after learning of the identities of the ghosts were to save the children from their corruption. Those intentions seem to be thrown away very soon though and the battle to save Miles and Flora becomes less about the children, and more about exposing the truth about Miles" relation to the ghosts. The governess feels that Miles has been far too corrupted to be saved, and therefore is looked upon almost angrily by her. This anger is strongly seen at the end of the story. In the final climactic seen in which Peter Quint appears to the governess, Miles seems rather confused and also seems to not know of his being there. It is in this scene that it can become clear to the reader that Miles was pretending to see the ghosts. He knows that the governess is worried about the ghosts being there because of the letter he stole that was addressed to the uncle, which most likely contained the concerns of the governess about Jessel and Quint. When the governess is yelling at Miles in this scene, Miles seems very confused and does not know where Peter Quint is, showing that he cannot see him. The governess is too caught up in her obsession with these ghosts and their corruption that she fails to notice Miles" reaction to her accusations and she kills him in her fit of anger. This is the interpretation suggested by the Masterpiece Theatre version of this story, and it also seems the most rational.