Henry James's novel The Turn of the Screw is essentially a horror novel that includes typical Gothic characteristics. As your comment indicates, sexuality is not a topic that is treated lightly in Victorian literature. One of such topics is "child corruption"which, in the novel, is the terminology used as an euphemism for child abuse in the form of sexual misconduct with children.
In an interesting choice of point of view, which is an element of form or structure, James places the character of Mrs. Grose as the primary witness of the alleged corruption of Flora and Miles at the hands of Miss Jessel and Peter Quint, respectively, when the latter two are working at the manor in Bly.
Mrs. Grose is an older woman with little education. She is presumably aware of what Jessel and Quint do to the children, and how "involved" they seem to be with them. However, how can she describe this to the governess? Or rather, how could Henry James send the message so that the reader understands what the corruption really is?
In a subtle manner, James chooses specific words that, when spoken by Mrs. Grose, bring out their true meaning due to the nature of her character.
For example, in chapter 6, Mrs. Grose explains to the governess the nature of Peter Quint's affection towards Miles by hinting at how "free" he is with everyone.
And you tell me they were‘great friends’?”
Oh, it wasn’t him!Mrs. Grose with emphasis declared. It was Quint’s own fancy. To play with him, I mean—to spoil him.” She paused a moment; then she added: Quint was much too free.
This gave me, straight from my vision of his face—such a face!—a sudden sickness of disgust. Too free with my boy?
Too free with everyone!
Similarly in chapter 7 it is hinted that the intentions of Jessel are just as wicked as those of Peter Quint. Furthermore, there is additional confirmation that Quint corrupts Jessel and that their ultimate goal is to possess the children. Jessel, who is described as a "former" lady, is a victim of Peter Quint like "everyone else". She is also an evil influence who knows Flora all too well. When the governess sees her apparition, she describes it as a bad and evil picture to Mrs. Grose
She stared at mine [eyes] as if they might really have resembled them. “Do you mean of dislike?”
“God help us, no. Of something much worse.”
Worse than dislike?—this left her indeed at a loss.
With a determination—indescribable. With a kind of fury of intention.”
I made her turn pale. “Intention?”
To get hold of her.Mrs. Grose—her eyes just lingering on mine—gave a shudder and walked to the window; and while she stood there looking out I completed my statement. “that’s what Flora knows
Therefore, in The Turn of the Screw, Henry James cleverly utilizes the point of view of two subservient women to address the delicate subject of child corruption within the parameters that mold Victorian literature. He creates a play on words to indicate a very shocking topic and he consistently holds the reader in doubt as to whether the governess is going insane and having hallucinations, or whether she is indeed the main protector of the children.