In Hatchet, what two true things come to Brian's mind after not being rescued by the plane?
At first, the plane flying over the lake without spotting him sent Brian into a depression. He had been unwilling to continue trying, unwilling to go on surviving and had begun wishing for it to simply end. He had let the fire go out, he simply sat and hoped for an end. He even went so far as to cut himself with the hatchet, hoping to end the process himself.
But once he realized that he had not killed himself, that he was still there, he also realized that he knew two true things about himself.
The first was that he was new, he had changed. He was not the same Brian that had crashed and survived for some time. He would never actually be like that Brian again for he had permanently changed.
The second true thing he realized was that he would not die, he would simply "not let death in again" the way he had when the plane flew over and did not rescue him.