Gee, this is the perfect place to leave Romeo. Up here in the old castle, no one will find him
Oh Romeo! Just one kiss- AGH PARIS
Now that Paris has successfully left town with Romeo's body, he is storing him up in the castle where he hopes no one will find him. Only a kiss from Juliet will be the cure to the deep sleep
Juliet always went down to the old castle with Romeo as a kid. Since she hasn't seen him for a while, she suspected he'd maybe be in their old hide out. However, she finds Romeo, goes in for the kiss and Paris casts the spell on her too so Che cannot be happily married to Romeo.
These two lovers love life ended in tragedy as they were banned from each other. Romeo and Juliet could've been spending forever together if it were for Juliet's kiss. Sometimes life gets in the way, and in this case it was Paris. If it weren't for him, Juliet would've broken the spell and spent eternity with Romeo.