This is easily one of the most emotionally charged scenes in the play!
Juliet basically tells her dad "thanks, but no thanks" regarding her marriage to Paris.
...And Lord Capulet loses it...
He calls her ungrateful and essentially says that if she doesn't get to the church on Thursday that he will disown her! He says that even if she's begging, starving and homeless, he will NOT EVEN ACKNOWLEDGE HER!
He also says that although he and his wife were at first grateful for getting her as their child, they are no longer happy because she is just too much to handle!
He also calls her some rather unsavory names--those you'll have to look up on your own :)
Juliet does her best to "fix" the situation on the surface by telling the Nurse to tell her parents that she'll marry Paris and that she'll go to confession to be absolved of her sin of being disobedient. Her parents, at that point, think all is well. In fact, her parents (esp her dad) go all out with the wedding preparations after that.
Lord Capulet is clearly absolutely furious when Juliet says she doesn't want to marry Paris. He says horrible things to her, including saying that he wished he had never had a child.
You would think that this would totally destroy their relationship, at least for a while. I would think that it would take quite a while to forgive that kind of statement, unless Lord Capulet really did a good job of apologizing to Juliet.
Of course, there is no need to wonder, because their relationship is done -- she'll be dead very soon.