Lady Capulet believes Juliet weeps for her dead cousin. Lady Capulet tells Juliet to dry her tears and expects the news of marriage to cheer Juliet up.
Well, well, thou hast a careful father, child;
One who, to put thee from thy heaviness,
Hath sorted out a sudden day of joy,
That thou expect'st not nor I look'd not for.
By saying "I look'd not for," she tells us that she is not involved in the planning of this, but when Juliet refuses, Lady Capulet simply tells her to bring it up with her father.
Lord Capulet is not pleased that his daughter refuses the match. He yells and calls her names, threatening to drag her out to the church if he has to. His words do shock Lady Capulet, and she says,
Fie, fie! what, are you mad?
However, Lord Capulet dominates the dialogue in this exchange. He refuses to hear any excuses or explanations from Juliet. Even the Nurse speaks up:
You are to blame, my lord, to rate her so.
But Lady Capulet's only other line in this exchange is:
You are too hot.
She says this to her husband. This is similar to her other line, as they both comment on his reaction. She is silent the rest of the time while Lord Capulet yells. According to the text, she definitely thinks her husband is overreacting. But she does not defend Juliet, and once he leaves, she says to her daughter
Talk not to me, for I'll not speak a word:
Do as thou wilt, for I have done with thee.
Because she only has two lines telling her husband he is too angry, much of her reaction is in silence and therefore left up to the actress portraying the character. When reading, we are left feeling like Lady Capulet has not done enough to defend her daughter. She seems to be an uncaring mother. Depending on the actress's facial expressions, perhaps this is because she is powerless against her husband. Perhaps she only married him because it was an arranged marriage. The actress could be cold during this scene, or she could look fearful of her husband.