In Act III of Hamlet, Hamlet says, "My tongue and soul in this be hypocrites." What does he mean?

To understand the quotation, it must be considered in
context. Hamlet is sickened by his mother's marriage to Claudius, viewing their
relationship as incestuous. His rage has grown, and he plans to confront her about her
betrayal of her love for Old Hamlet and her sinful behavior with Claudius. Before
entering her chamber, Hamlet anticipates what will occur--and must not
occur:

O
heart, lose not thy nature; let not ever

The soul of Nero
enter this firm bosom.

Let me be cruel, not
unnatural;

I will speak daggers to her, but use
none.

My tongue and soul in this will be
hypocrites.

Hamlet intends to
speak with cruelty to his mother, but he loves her. He must not lose control and harm
her. To do so would violate the natural love between them. He will "speak daggers," but
he will use no weapon against her. His words and actions (his "tongue and soul") will be
hypocritical, therefore, since they will not reflect his deep love for his mother; he
will not mean everything he is about to say.