I would want to argue that the central conflict that is resolved during the course of this excellent play is the conflict between John and his wife, Elizabeth. In the final act, when John and Elizabeth are given time to spend together having been separated and jailed for three months, they are able to finally resolve the differences that they have. After Elizabeth confesses her role in their division, note how she counsels John:
Do what you will. But let none be your judge. There be no higher judge under Heaven than Proctor is! Forgive me, forgive me, John--I never knew such goodness in the world.
With these final words it is clear that their love for each other is resurrected and their acceptance of each other is likewise re-established. Elizabeth's final words as John goes off to be hung, "He have his goodness now. God forbid I take it from him!" speaks of an amazing pride and love, indicating the healing of the breach between them.