Paris is still hanging around hoping he can marry Juliet.
Unfortunately, Juliet's still way depressed about Tybalt/ Romeo.
Juliet's grief for Tybalt seemed so extreme to her father that he's changed his mind about waiting a few years before she is married. What better way to cheer her up than to force her into a marriage with a man she's just not that into?
Figuring that there's no way Juliet could refuse a great guy like Paris, Lord Capulet decides to go full speed ahead. How about marrying her next week? he asks Paris.