Yes there's going to be a literature component and probably history and politics, although OP's Italian equivalent of high school might have prepared him for those somewhat.
Not that this happened, but there absolutely would have been at least one suspicion. Nobody doesn't have an accent of some sort, and he'd have no way of knowing how accurate his pronunciation is all the way from Italy among other Italians. Everyone thinks they sound good til they hear themselves on a recording. His only way out would be to say his family is italian-american but he doesn't know the language very well. He might think of that. He's also on 4chan, though.
However, Americans are highly curious about others as a rule and the women reportedly thought he was at least ok, so someone would have asked where he was from regardless of what he sounded like. And then he would have been stuck playing 20 questions about a randomly chosen region he isn't familiar with and hoping to god whoever he's talking to isn't from there.
Language has nothing to do with intelligence, why does that one bit matter? It's your environment that matters for language, there are plenty of stupid people from Europe or India or whatever who speak 2-5 languages like anyone else would... there are also plenty of Italians who are native English speakers because they grew up watching content by English-speaking people online (I know a few myself)