What is the purpose of Kalfala's secret something?
A "confidence" is a small secret; something that you are told that you should not pass along. For something to be "confidential", then this is something that should be kept private, and not distributed. In the military, "confidential" is the lowest level of security classification, followed by "Secret" and "Top Secret".
Destination has more than one meaning; mainly: the purpose for which something is destined an act of appointing, setting aside for a purpose, or predetermining a place to which one is journeying or to which something is sent (e.g. kept their destination secret) a place worthy of travel or an extended visit (e.g. a destination restaurant or a destination resort).