How do both Capulet and lady Capulet expect their daughter to react to the news of her wedding?

First, a word of warning: when reading Shakespeare, it's important not to apply 2013 attitudes to how the world was in the 1500s. In our modern world, women choose their own husband, or they decide they don't want to marry. Except for countries where their is still arranged marriage (conducted by the girl's parents), most western countries today accept the idea that the choice of a marriage partner should be left up to the woman and the person she loves.

But in Shakespeare's day, women still had no legal rights under the common law. They were, for all intents and purposes, the property of first their father and later their husband. Granted, some men treated their wives and daughters well, but they were under no legal obligation to do so. Thus, when the parents of Juliet wanted to choose a husband for her, and when they decided it was time for her to marry, she would have been expected to accept it. Certainly, some girls objected, but there was not much they could do other than beg their parents to reconsider. Thus, how Juliet might react was not that much of a factor to her parents, who believed they knew what was best for her.

Actually, the above is not wholly true. Under common law, only married women were considered to have no rights of their own (the rights of the married couple could be exercised by the husband and occasionally by the wife, which is why wives could pledge their husbands' credit). And there is no reason to suppose that sixteenth century girls were married against their will any more than they are today. To be sure, there were issues of dowry to be settled: a good prospect as a husband might expect to get a whack of money from the father for marrying his daughter. But the girl's consent, freely given, was essential.

If you examine Shakespeare's own life, it is clear that he and Anne chose each other without the aid of their parents. Susannah's husband got a sizeable settlement, but he was a doctor and a good catch. Although the parents must have been involved in this wooing process, there is no reason to think that Susannah did not want to become Mistress Hall. Judith's husband did not get much money for marrying her (the Shakespeares had probably blown their wad on Dr. Hall) and Shakespeare did not like him. But Judith married him anyway, and Shakespeare was forced to try to draw his will so that he would never get any of Shakespeare's money.

Furthermore, if you look at Shakespeare's plays, our sympathy is intended to be with the girl every single time, and not with the parents. We are meant to sympathize with Juliet, not the Capulets. Nobody ever left that play saying, "That's what she deserved for being disobedient." Nor has anyone ever sympathized with Egeus in A Midsummer Night's Dream as opposed to Hermia, or the Pages as opposed to their daughter Anne in The Merry Wives of Windsor, or Brabantio as opposed to Desdemona in Othello. The only arranged marriage that we are led to approve of is the one in All's Well that Ends Well, and in that case, it is not a daughter who is bucking the marriage, but a son. In other words, women should not be forced to marry against their wills, but it is OK to force men to do so.

Since we know that Shakespeare drew many of his plotlines from earlier material (Romeo and Juliet is an example), this plot device of the young woman being forced to marry someone against her own will is a relic of an earlier time, when public opinion was turning against arranged marriages in Europe. It worked in Shakespeare's day and works with us, because they did not approve of such forced marriages any more than we do.