Act 5 Scene 3

Juliet
Yea, noise? then I'll be brief. O happy dagger!
Snatching Romeo's dagger
This is thy sheath;
Stabs herself
there rust, and let me die.
Falls on Romeo's body, and dies
Enter Watch, with the Page of Paris

Thanks to http://shakespeare.mit.edu/romeo_juliet/romeo_juliet.5.3.html