Meaning of がな at the end of this sentence

Question

What is the meaning of がな at the end of the following sentence? (I divided it into 3 pieces because this is how it's written on the manga page it is taken from. Source: https://i.sstatic.net/vSnlY.jpg)

"齋藤仁【さいとうじん】"がそういうんじゃねえってことくらいは // ずっと見続けてきてんだわかる // 口では絶対【ぜって】ェ言ってやんねえがな

I read on dictionaries that がな can indicate a wish, or uncertainty, but I think it has just an emphatic value in this case. My attempt:

"Jin Saito" is not what he looks like / I know it 'cause I've always watched him / (But?) There's no way I can say it

I would also be grateful if you could correct any error in my translation, thank you!

Answer 1

「～～～がな」＝「～～～　+ が + な」＝「～～～ + けど + な」

In this context,

「が」＝「けど」＝ "though", "although".

「な」 here is a sentence-ending particle expressing a light kind of declaration.

「絶対{ぜって}​ェ言ってやんねえがな」

therefore, is Kanto tough guy speech for:

「絶対{ぜったい}言ってやらないけどな」

= "There is no way I'm gonna tell him, though."