Romeo and Juliet being written in verse makes it seem more like a love poem.
In Shakespeare’s day, a young man would write a young lady a sonnet to show her that he loved her. This is why the verse is so effective in Romeo and Juliet. It is a very lyric play, and many characters speak beautifully. During the party, Romeo and Juliet share a sonnet. What could be more romantic?
Have not saints lips, and holy palmers too?
Ay, pilgrim, lips that they must use in prayer.
O, then, dear saint, let lips do what hands do!
They pray; grant thou, lest faith turn to despair.(Act 1, Scene 5, p. 32)
The sonnet is both a witty exchange and an expression of love. When the two of them talk to each other like this, they are the only people in the room.
Romeo and Juliet’s exchanges are almost always poetic. When he hides in her courtyard, Romeo compares Juliet to the sun. She expresses frustration about what a name really means.
What's Montague? it is nor hand, nor foot,
Nor arm, nor face, nor any other part
Belonging to a man. O, be some other name!
What's in a name? That which we call a rose(45)
By any other name would smell as sweet. (Act 2, Scene 2, p. 39)
The fact that the two young lovers talk to each other so sweetly reinforces the fairy tale nature of their love story. Their dialogue is unnatural, because their love is unnatural.
By having them talk about each other in verse, and talk to each other in verse, Shakespeare creates a beautiful insular world just for them. The audience is transported with them, and entirely accepts the depth of their love despite their quick relationship. The verse therefore helps with the suspension of disbelief. The audience has to accept their love story in order for the tragedy to have full effect.