What emotion and figurative language does Shakespeare use in act 3, scene 3 of Romeo and Juliet, during Romeo's monologue "'Tis torture, and not mercy, heaven is here"?

The context of Romeo’s monologue is particularly important for its analysis. In act 3, scene 1, Romeo kills Tybalt, a Capulet, out of revenge for killing Mercutio. In response, rather than have Romeo killed, Prince Escalus banishes him from Verona. This action is exceedingly sympathetic; Prince Escalus is ignoring traditional law, as he himself leans toward the Montague family and detests the Capulets. Immediately before Romeo’s monologue, Friar Lawrence tries to make Romeo understand that his exile is a form of mercy.

'Tis torture and not mercy. Heaven is here,Where Juliet lives, and every cat and dogAnd little mouse, every unworthy thing,Live here in heaven and may look on her,But Romeo may not. More validity,More honorable state, more courtship livesIn carrion flies than Romeo.

“Heaven is here” and “here in heaven” contain alliteration through repetition of the H sound. Heaven is a symbol for Verona (i.e., where Juliet is). By extension, Romeo is implying that Juliet is an angel. To equate Verona with heaven, simply because Juliet is there, is hyperbolic; the play features conflict and bloodshed between the Montagues and Capulets in Verona, and it is quite an exaggeration to imply that Juliet is a divine being. “More validity, more honorable state, more courtship lives in carrion flies” means that flies are more worthy to be Juliet’s love than Romeo. This line contains personification, by giving flies the human capability of love. Repetition is also established with the word “more,” but in this case it is classified as anaphora because the sentence begins with the repetitive word.

They may seizeOn the white wonder of dear Juliet’s handAnd steal immortal blessing from her lips,Who even in pure and vestal modesty,Still blush, as thinking their own kisses sin.But Romeo may not. He is banishèd.Flies may do this, but I from this must fly.They are free men, but I am banished.

“White wonder” contains alliteration with the repetition of the W sound. “Immortal blessing” and “pure and vestal modesty” are allusions to Juliet being an angel and a virgin, respectively. Romeo says that Juliet blushes when her lips touch, believing this to be a sin (this is also hyperbole). Moreover, the personification of flies is extended to compare them to men entirely, making Romeo’s words even more dramatic. “Flies may do this, but I from this must fly” is a pun, or wordplay.

And sayst thou yet that exile is not death?Hadst thou no poison mixed, no sharp-ground knife,No sudden mean of death, though ne'er so mean,But “banishèd” to kill me?—“Banishèd”!

Romeo’s words are hyperbolic, as he equates his banishment to death because he cannot physically be with Juliet. Repetition is also established with the word “no.”

O Friar, the damnèd use that word in hell.Howling attends it. How hast thou the heart,Being a divine, a ghostly confessor,A sin-absolver, and my friend professed,To mangle me with that word “banishèd”?

In this passage, Romeo says that damned souls in hell use the term “banished.” He asks Friar Lawrence, as a man of God and his friend, how he can use such a term as is used by souls sent to hell. “How has thou the heart” is an example of both alliteration and assonance through the repetition of the H sound and the vowel sound made by the endings of “how” and “thou.” Note that Romeo is not saying Friar Lawrence is divine; rather, the meaning is established in combination with the metonymies of “ghostly confessor” and “sin-absolver,” signifying that he is a member of the church.