In the famous balcony scene in Act II, Scene 2, Juliet brings up the important subject of marriage when she says to Romeo:
If that thy bent of love be honourable,
Thy purpose marriage, send me word to-morrow,
By one that I'll procure to come to thee,
Where and what time thou wilt perform the rite;
And all my fortunes at thy foot I'll lay
And follow thee my lord throughout the world.
In Act II, Scene 3, Romeo goes to Friar Laurence for the express purpose of asking the friar to marry him to Juliet.
Then plainly know my heart's dear love is set
On the fair daughter of rich Capulet;
As mine on hers, so hers is set on mine,
And all combin'd, save what thou must combine
By holy marriage.
At the end of this scene, Friar Laurence expresses his agreement to perform the marriage because he believes the union of the two members of the feuding families would lead to a reconciliation of the Montagues and Capulets.
In Act III, Scene 5, Romeo and Juliet appear "ALOFT, AT THE WINDOW." They are obviously now lawfully married and have spent the night together. Romeo must leave Verona immediately, since he has been banished for killing Tybalt. Juliet is so intoxicated by love that she tries to detain him just a little while longer. She tells him:
It was the nightingale, and not the lark,
That pierc'd the fearful hollow of thine ear.
In Act V, Scene 3, Romeo addresses Juliet, who is in a drug-induced coma, as:
O my love! my wife!
And Friar Laurence explains to the Prince near the end of the play:
Romeo, there dead, was husband to that Juliet;
And she, there dead, that Romeo's faithful wife.
The love between Romeo and Juliet is represented as real and pure because of their eagerness to affirm it by marriage. The fact that the members of their respective families hate each other is of no significance to either of them. Their love overrides the hatred of generations of Montagues and Capulets.