>>617
I often had/have this trouble with classics.
Case 1: the words and phrases that are easily judged as meaning the opposite (irony/sarcasm) by people from one decade can be confusingly ambiguous in another. The use of such is an integral part of English (in particular, but not exclusively) over the centuries, but the ways we say it are like slang that goes in and out of fashion.
Case 2: it's not always clear just from reading whether it's the character's, author's, or generation's view(s) that is causing you to question the sincerity/irony of what was stated. Like, it's so much simpler to understand someone's point if you know what else they believe and the context of those beliefs (ideologies, factions, mores).