In America, we also recognise this kind of person with a colloquial expression. We call them "as good as gold."
That's about right.
In Italy, when someone is trying to trick you, and you aren't going to fall for it, you say, "I'm not drinking it" (implying that someone is trying to give you low-quality wine, of course).
In America, we also aren't taking any BS. But instead we say, "I'm not buying it."
And this is just about all you need to know about the cultural differences between Italy and the US...