The Turn of the Screw: the governess is a liar

In the previous post, I called the governess an unreliable narrator. 
Now I’m going to call her a liar. 
Look at this conversation between her and Mrs Grose in chapter 7: 

“Then, as she released me, I made it out to her, made it out perhaps only now with full coherency even to myself. “Two hours ago, in the garden”—I could scarce articulate—“Flora saw!”
Mrs. Grose took it as she might have taken a blow in the stomach. “She has told you?” she panted.
“Not a word—that’s the horror. She kept it to herself! The child of eight, that child!” Unutterable still, for me, was the stupefaction of it.” 

Let’s go back: 

“My heart had stood still for an instant with the wonder and terror of the question whether she too would see; and I held my breath while I waited for what a cry from her, what some sudden innocent sign either of interest or of alarm, would tell me. I waited, but nothing came; then, in the first place—and there is something more dire in this, I feel, than in anything I have to relate—I was determined by a sense that, within a minute, all sounds from her had previously dropped; and, in the second, by the circumstance that, also within the minute, she had, in her play, turned her back to the water. This was her attitude when I at last looked at her—looked with the confirmed conviction that we were still, together, under direct personal notice. She had picked up a small flat piece of wood, which happened to have in it a little hole that had evidently suggested to her the idea of sticking in another fragment that might figure as a mast and make the thing a boat. This second morsel, as I watched her, she was very markedly and intently attempting to tighten in its place. My apprehension of what she was doing sustained me so that after some seconds I felt I was ready for more. Then I again shifted my eyes—I faced what I had to face.” (Ch.6) 

Does that sound like Flora’s aware of someone else’s presence? Not necessarily.
Also, as written before, the governess can’t see very well and at the beginning wonders if it could be a postman or some boy, so I don’t know how she jumps from that to the conclusion that it’s Miss Jessel that she sees. 
Another conversation between her and Mrs Grose: 

““Everything. It doesn’t matter. I’ve made up my mind. I came home, my dear,” I went on, “for a talk with Miss Jessel.”
I had by this time formed the habit of having Mrs. Grose literally well in hand in advance of my sounding that note; so that even now, as she bravely blinked under the signal of my word, I could keep her comparatively firm. “A talk! Do you mean she spoke?”
“It came to that. I found her, on my return, in the schoolroom.”
“And what did she say?” I can hear the good woman still, and the candor of her stupefaction.
“That she suffers the torments—!”
It was this, of a truth, that made her, as she filled out my picture, gape. “Do you mean,” she faltered, “—of the lost?”
“Of the lost. Of the damned. And that’s why, to share them—” I faltered myself with the horror of it.
But my companion, with less imagination, kept me up. “To share them—?”
“She wants Flora.”” (Ch.16) 

Again, let’s go back. 

“Seated at my own table in clear noonday light I saw a person whom, without my previous experience, I should have taken at the first blush for some housemaid who might have stayed at home to look after the place and who, availing herself of rare relief from observation and of the schoolroom table and my pens, ink, and paper, had applied herself to the considerable effort of a letter to her sweetheart. There was an effort in the way that, while her arms rested on the table, her hands with evident weariness supported her head; but at the moment I took this in I had already become aware that, in spite of my entrance, her attitude strangely persisted. Then it was—with the very act of its announcing itself—that her identity flared up in a change of posture. She rose, not as if she had heard me, but with an indescribable grand melancholy of indifference and detachment, and, within a dozen feet of me, stood there as my vile predecessor. Dishonored and tragic, she was all before me; but even as I fixed and, for memory, secured it, the awful image passed away. Dark as midnight in her black dress, her haggard beauty and her unutterable woe, she had looked at me long enough to appear to say that her right to sit at my table was as good as mine to sit at hers. While these instants lasted, indeed, I had the extraordinary chill of feeling that it was I who was the intruder. It was as a wild protest against it that, actually addressing her—“You terrible, miserable woman!”—I heard myself break into a sound that, by the open door, rang through the long passage and the empty house. She looked at me as if she heard me, but I had recovered myself and cleared the air. There was nothing in the room the next minute but the sunshine and a sense that I must stay.” (Ch.15) 

There is no conversation here. If the spirit of Miss Jessel does appear, which I doubt, she does not speak. The governess says “the awful image passed away” and “there was nothing in the room the next minute”. 
Isn’t it obvious now that she lies? 
Then in chapter 18, Miles plays some music, then the governess realises that Flora’s gone. She looks around and asks Mrs Grose. 

““No; she’s at a distance.” I had made up my mind. “She has gone out.”
Mrs. Grose stared. “Without a hat?”
I naturally also looked volumes. “Isn’t that woman always without one?”
“She’s with her?”
“She’s with her!” I declared. “We must find them.”” 

Note that Mrs Grose never says anything about Miss Jessel not wearing a hat. It’s Peter Quint that she says a few times doesn’t wear one. 
Again she has a baseless assumption. Then she goes further: 

“My hand was on my friend’s arm, but she failed for the moment, confronted with such an account of the matter, to respond to my pressure. She communed, on the contrary, on the spot, with her uneasiness. “And where’s Master Miles?”
“Oh, he’s with Quint. They’re in the schoolroom.”
“Lord, miss!” My view, I was myself aware—and therefore I suppose my tone—had never yet reached so calm an assurance.” (Ch.18) 

That confidence comes from nothing. There is no evidence, only conjecture, or I would rather say, lies. The governess is dishonest, and she manipulates the simple Mrs Grose. For what? 
It doesn’t stop there. 

“Mrs. Grose still stood where she had stopped. “You suppose they really talk of them?”
“I could meet this with a confidence! They say things that, if we heard them, would simply appall us.”” (Ch.19) 

See how ridiculous that sounds? She makes stuff up.
So far, everything in The Turn of the Screw suggests that the governess is manipulative and an unreliable narrator. 
There are only 3 arguments for the other interpretation (that the ghosts exist and the children are evil). 1, the unexplained and unexplainable expulsion, especially considering Miles’s intelligence and good manners. 2, the framed narrative structure, and the fact that the other narrator speaks well of her (though I’m not sure he’s reliable enough to attest to her reliability). She can still be a good person who has a nervous breakdown at that point and imagines things. 3, she can describe the looks of Peter Quint. Note that she never describes Miss Jessel, only that she wears black and is beautiful—the word “pretty” comes from Mrs Grose. She does describe Quint, but it’s not impossible that she has seen the image somewhere, which is what happens in the film. The story is not recorded in a diary, but written down long after the events, and one can mix up the order of events. 
 Maybe I’m too rational to enjoy The Turn of the Screw as a ghost story, but so far everything adds up to the interpretation that it’s all in her head.