There’s lots of gender-bending in Shakespeare’s comedy Twelfth Night. The heroine of the play, Viola, dresses up as a man (Cesario) after she’s shipwrecked on the coast of Illyria. Her disguise manages to fool everyone, including a Countess named Olivia, who falls in love with the Cesario version of Viola, and the Duke of Illyria, Orsino, with whom the Viola version falls in love.
Stephen Greenblatt wrote a famous essay on this play called “Fiction and Friction” in his book Shakespearean Negotiations. In the essay he talks about how Twelfth Night challenges Elizabethan gender and sexual norms, and also affirms those norms at the same time.
So, let’s look at this excerpt below. In it, Duke Orsino is addressing Viola (who is disguised as Cesario). At this point the Duke doesn’t know that Cesario, who has become his page, is actually a woman. The Duke is in love with the Countess Olivia (or he thinks he is). He decides to send Viola/Cesario to Olivia with messages of his love for Olivia.