Juliet is talking about how badly she wants to easily be able to be with Romeo
"O, I have bought the mansion of love but not yet possessed it "
"Can heaven be so envious?"
The nurse comes in trying to tell Juliet that Tybalt is dead but Juliet thinks she's talking about Romeo. The nurse is showing Dramatic Irony by what she's saying
"Romeo can, though heaven cannot. O Romeo, Romeo, whoever would have thought it? Romeo!"
"Dove-feathered raven, wolvish-ravening lamb! Despisèd substance of divinest show!"
The nurse explains to Juliet that Romeo isn't dead but he's the one that killed Tybalt and that Romeo is now banished. Juliet is mad at Romeo and is expressing her rage through oxymorons
"Tybalt is gone and Romeo banishèd. Romeo that killed him- he is banishèd."
"O, what a beast was I to chide at him!... That "banishèd," that one word "banishèd," Hath slain ten thousand Tybalts"
Juliet realized this means she won't be seeing Romeo and immediately regrets saying all the bad things she said about him. This shows that Juliet changes her emotions suddenly and cares a lot about love
"O, find him! Give this ring to my true night and bid him to come to take his last farewell"
The nurse tells Juliet that she will go find Romeo to comfort her. This shows that the nurse is compassionate and obedient towards Juliet
"Hie to your chamber. I'll find Romeo to comfort you."