Marx – ladies and gents – was truly a "tough guy".
Is this sentence OK? I mean the postition of the indefinite article? Why is it not placed before the word "truly" as in the sentence "he was a very tough guy"?
The author does not mean that Marx was a truly tough guy (= a very tough guy) but that he was truly (in truth, in fact) a tough guy and not something else (which is presumably described elsewhere in the discourse—for instance, a sentimental do-gooder or an armchair theorist).