In Act 2, line 34, Juliet states "Deny thy father and refuse thy name,
Or if thou wilt not, be but sworn my love,
And I'll no longer be a Capulet."
I can not be with you because you are a Montague.
Tell your father that you refuse to marry anyone other than me.
If you will give up your name, I will give up my name, and we can be together.
I won't be a Capulet anymore when I marry you.