because I wanted to see Jane

[azz]

- You went to the party because you wanted to see Jane.
-No. I didn't go to the party because I wanted to see Jane. Actually I didn't go to the party at all.

As far as I know
"I didn't go to the party because I wanted to see Jane." either means
a) As I wanted to see Jane, I didn't go to the party. If I had gone to the party I wouldn't have seen Jane, therefore I didn't go.
or
b) I went to the party, but not because I wanted to see Jane. I went for another reason.

The question is whether that sentence works in the conversation above where the speaker is repeating something someone else has already said to refute it. Here he is saying that it is not true that he went to the party to see Jane, because he did not go to the party at all.

 

[Tarheel]

Let's clear up the mystery. If somebody said, "I didn't go to the party because I wanted to see Jane" I would assume that the speaker did go to the party, but seeing Jane was not the reason. The speaker in your invented conversation knows full well that's what people would think. Therefore, the first sentence is immediately followed by an explanation. In other words, not only did he not go to the party to see Jane. He didn't go at all.

The humor is relatively mild, but it's there.