Haven has the following meanings:-
1. A harbor or anchorage; a port: “Bombay harbor is a haven for many ships belonging to different countries.”
2. A place of refuge or rest; a sanctuary: “When in trouble people go to religious places considering them a haven.”
Heaven , on the other hand, has the following meanings:-
1. The sky or the universe as seen from the earth; the firmament: “Certain trees are so tall that they seem to be touching the heavens.”
2. The abode of God, the angels, and the souls of those who are granted salvation: “Man can enter heaven only if he has done noble deeds and has lived a pious life.”
3. An eternal state of communion with God; everlasting bliss: “I felt I was in heaven when I visited Kashmir for the first time.”