All the other people are attatched to chains accept the farmer he hase a rope but how do you snap it? I saw the rainbow lock was rope too do i have to make a line of rope as a key?
You're mostly on the right track! The rainbow lock has too many colors for a single key, but rope can easily be cut with your sword. Just use your sword on the box and it will cut the rope.
Or the master key if you collected all goodies,