Originally, when bill Hastings was telling his wife what happened with Ruth, he said it was a dream. But when interviewed by Tammy he says it was real. In both instances, he says this in the manner of someone who is utterly sure what he is saying is true.
Maybe he was rationalizing it as a dream when he told his wife; knowing she wouldn't believe the reality, but he was compelled to speak about it anyhow.
Later, when being interviewed, he felt he had an attentive and understanding listener, and felt compelled to tell the truth as he understood it, no matter how strange it would appear to others.
Yes, that's probably it.