Act II, scene iv, 103-110
Well, sir, my mistress is the sweetest lady.—Lord, Lord! when 'twas a little prating thing.—Oh, there is a nobleman in town, one Paris, that would fain lay knife aboard, but she, good soul, had as lief see a toad, a very toad, as see him. I anger her sometimes and tell her that Paris is the properer man. But, I'll warrant you, when I say so, she looks as pale as any clout in the versal world. Doth not rosemary and Romeo begin both with a letter?
Basically, she is saying this:
Well, sir, my mistress is the sweetest lady. Lord, Lord, when she was a little baby—Oh, there is one nobleman in the city, a guy named Paris, who would be happy to claim her as his own. Juliet would rather look at a toad than at him. I make her angry sometimes by saying that Paris is more handsome than you are. But when I say so, I swear she turns white as a sheet. Don't “rosemary ” and “Romeo” begin with the same letter?