Is the following Japanese sentence negative or positive in English?

Question

Context: Character A has just told the character who is the narrator that he has the talent to be an assassin. Being a normal person, and thus taken off guard, the narrator responds with the following:

「はは……、わけの解【わか】らないこと言わないでくれよ。大体、何の根拠があって……」

From what I can tell, the narrator says something along the lines of:

"Haha……, it’s nearly impossible for me to understand the thing you’re not saying that I have. In the first place, on what basis do you say that……"

I think that the italicized part of the English sentence corresponds to the bold bit in the Japanese which emphasizes the narrator's disbelief, but I'm unsure if my understanding of the Japanese is correct in terms of the sentence being an emphasized negative sentence, a double negative, or a positive created from two negatives.

What is the correct way of understanding the above Japanese sentence, given the context?

Answer 1

• 訳が分からない (or 訳が分からん, わけわからん, etc) is an extremely common set phrase meaning "nonsensical", "puzzling", "garbled", etc. 訳が分からないこと or 訳の分からないこと as a whole means "gibberish", "rubbish", etc. (解る is another way of writing 分かる in novels and such.)
• 言わないでくれ is "(please) don't say ～". I believe you know te-form + くれ is a way of making a request. Naturally, ～ないでくれ is a negative version of it.
• 訳の分からないこと is the object of 言う. を has been omitted because this is informal speech.

Therefore, the translation of わけの解らないこと言わないでくれよ is very simple: "Don't talk nonsense."