Jer. is talking about not putting your faith in man.
Ahhh nuts! Instead of citing Jeremiah 17:5, I should have cited 17:7. "Blessed is he who trusts in the LORD, Whose trust is the LORD alone." I tend to think of the curse and the blessing as two sides of the same coin. [My reasoning: Can't love the LORD with your whole being and trust Him completely and turn your thoughts from Him simultaneously, no?]
Okay, so replace Jeremiah 17:5 with 17:7 in my OP and change my first question to: Can a Jew love and trust the Lord completely and believe things that are not true?
Something tells me that your next inquiry will ask me what kind of false things do I have in mind? And that's a big chunk of what I'm looking for and why I'm asking.
I'm still trying to sort the "things" part of my question out in my mind: What things does a Jew have to know correctly in order to love and trust the LORD completely?
In all likelihood my questions are going to evoke curiosity: i.e. why do I want to know?
My answer: Because they're just the beginning. And no, this thread is NOT a surreptitious proselytization ploy.