In Act 2, Scene 2, Juliet is portrayed by Shakespeare as being the more sensible member of the couple. We see her sensibleness in several places.
First, when she discovers that Romeo has scaled her family's garden wall to see Juliet again, her first very rational and sensible response is to fear Romeo is endangering his life. When she finds him in the garden, several times she reminds him that her family members will kill him if any of them see him.
Another way in which she acts sensibly is in feeling uncomfortable with exchanging vows of love with Romeo so soon. We see her express her sensible hesitation in her lines:
Well, do not swear. Although I joy in thee,
I have no joy of this contract to-night.
It is too rash, too unadvis'd, too sudden;
Too like the lightning, which doth cease to be
Ere one can say "it lightens." (II.ii.122-26)
Finally, she also acts sensibly by demanding that if Romeo's intentions are "honourable," he send her word about plans for marriage the next day (148-50). While it is a bit rash of her to want to marry so suddenly, it is also very sensible of her to stick with her principles and religious beliefs, showing us that ultimately she is more sensible than Romeo