To see what Irving has to say, all you have to do is look at the last paragraph of the story. However, it's still pretty ambiguous.
Irving says that not everyone in the village believes Rip's story. But thenhe says that they are just pretending not to believe. Irving also sort of implies that maybe people shouldn't believe it because Rip kept changing the story.
But, on the other hand, he says that all the old-time people in the village know it's true. They know that there really are supernatural things out there in the woods and hills.
So, Irving says that some don't believe him (maybe) and some do believe him.