Destiny is a title of Divine Knowledge it is not something that annuls man's free will and forces him to behave in a pre-ordained way. Since God knows beforehand how man will behave in the world. He has an angel to pre-record his life history. Man behaves according to the dictates of his free will not because God pre-recorded his future life.
Destiny is related both to the cause and effect. There are not two separate destinies one for the cause and the other for the effect. God knows beforehand how His servant will behave in what circumstances and His pre-knowledge does not contradict man's having free will.
No one except God knows whether a man will go to Paradise or Hell; although unbelief deserves eternal punishment we may not judge an unbeliever as being destined to Hell. It is possible that one day that unbeliever will accept faith and ultimately go to Paradise.