He uses "visual rhetoric" in the silent interview:
Lord Hamlet, with his doublet all unbraced;
No hat upon his head; his stockings foul'd,
Ungarter'd, and down-gyved to his ancle;
Pale as his shirt; his knees knocking each other;
And with a look so piteous in purport
As if he had been loosed out of hell
To speak of horrors,--he comes before me.
Later, Hamlet will use written poetic rhetoric to reveal his love for Ophelia:
From here on out, Hamlet's rhetoric to Ophelia is a kind of rant against his mother. He never seems to speak to Ophelia directly. He either speaks to her by proxy, knowing she will tell her father all. Hamlet knows the walls have eyes and ears, that nothing he hears from Ophelia can be trusted, that all he says to her will be trusted too much (analyzed to death by Polonius).
Then, he speaks to Ophelia as if she were his mother. He rants against marriage, against women, against trust and beauty. His mother's betrayal has deeply hurt him. He certainly can't channel his revenge against Gertrude; the ghost has not permitted it. So, he must channel it through the only woman he can: Ophelia. The most famous exchange of Hamlet talking to his mother through Ophelia is when he says:
I say, we will have no more marriages:
those that are married already, all but one, shall
live; the rest shall keep as they are. To a
The only words we can trust of his to Ophelia are his poetic ones. Hamlet trusts art (poetry) to reveal himself completely, not words in conversation. So, Hamlet's conversations with her are role-playing, method-acting games--performances that he uses to ultimately "catch the conscience of the king." Unfortunately, Ophelia gets caught in the crossfire.