How to signal curiosity?

At LessWrong we encourage people to be curious. Curiosity causes people to ask questions, but sometimes those questions get misinterpreted as social challenges or rhetorical techniques, or maybe just regular questions that you don’t have a “burning itch” to know the answers for (and hence maybe not particularly worth answering). I sometimes preface a question by “I’m curious,” but of course anyone could say that so it’s not a very effective way to distinguish oneself as being genuinely curious. Another thing I sometimes do is to try to answer the question myself and present one or more answers as my “guesses” and ask if one of them is correct, since someone who is genuinely curious is more likely put in such effort. But unfortunately sometimes that backfires when the person you’re directing the question at interprets the guesses as a way to make them look bad, because for example you failed to hypothesize the actual answer and include it as one of the guesses, and all your guesses make them look worse than the actual answer.

I’ve noticed examples of this happening to others on LW (or at least possibly happening, since I can’t be sure whether someone else really is curious) as well as to myself, and can only imagine that the problem is even worse elsewhere, where people may not give each other as much benefit of doubt as we do around here. So my question is, what can curious people do, to signal their genuine curiosity when asking questions? Has anyone thought about this question already, or perhaps can recognize some strategies they already employ and make them explicit for the rest of us?

ETA: Perhaps I should say a bit more about the kind of situation I have in mind. Often I’ll see a statement from someone that either contradicts my existing beliefs about something or is on a topic that I’m pretty ignorant about, and it doesn’t come with an argument or evidence to back it up. I’d think “I don’t want to just take their word since they might be wrong, but there also seems a good chance that they know something that I don’t in which case I’d really like to know what it is, so let’s ask why they’re saying what they’re saying.” And unfortunately this sometimes gets interpreted as “I’m pretty sure you’re wrong, and I’m going to embarrass you by asking a question that I don’t think you can answer.”

ETA2: The reason I use “signal” in the title is that people who do just want to embarrass the other person would want to have plausible deniability. If it was clear that’s their intention and it turns out that the other person has a perfectly good answer, then they’ll be the one embarrassed instead. So ideally the curious person should send a signal that can’t be faked by someone who just wants to pretend to be curious.