You might be tempted to argue, "Why doesn't Juliet just run away?" - but why is this not possible

Answer: She cannot run away because of her parents. There are men all around her chambers, watching over her.

Explanation:

She would certainly run away with Romeo if it wasn't for her controlling parents. In this play, Shakespeare does not only tell us a love story - he writes about the warring families of Capulets and Montagues.

In Act II, Scene II, Romeo climbs the wall built around the Capulet's property, and she is wondering how he managed to do so, since the walls are extremely high. We also find out in this scene that her "kinsmen" (men recruited by her father) watch over her to assure that no one enters her chambers. This situation makes it impossible for her to run away. Moreover, we find out during her conversation with the nurse, that she has to ask for a permission whenever she wants to go out. Given the circumstances, it is not possible for her to run away.