What can we really say about reality? We can say what we perceive, with 100% certainty. But we don't have 100% certainty that what we perceive does exist as we see it. In fact, we can never have 100% certainty of that.
Knowledge is justified true belief. Is any belief really justified? No. Beliefs can be true but we can never really know that they are true, at least not in a way that we can prove to ourselves with words.
So what is really safe to say? I think I can say "I honestly think X is true, but I could be wrong". We make statements that directly or indirectly make truth claims all the time, and sometimes it would make sense for us to rephrase them as "I honestly think X is true, but I could be wrong" but other times, it would undermine what we were trying to accomplish with our truth claim.
One example of the latter could be when people attack a belief, saying "But you don't really know that." If they stated that truth claim honestly, it would be "I honestly believe that you don't really know that, but I could be wrong". If this changes how the statement feels in the conversation such as to undermine the attacker, then there was something dishonest about the initial attack.
I got the form "I honestly think X is true, but I could be wrong" from reading Alvin Plantinga, so we could say that when a conversational act can be successfully rephrased as "I honestly think X is true, but I could be wrong", it is "Plantinga-compliant" and if not "not Plantinga-compliant" or "Plantinga-noncompliant".
Are there perhaps some statements that should not be stated so humbly as in Plantinga compliance? It does sound odd to say "I honestly believe if you step out into traffic you will die, but I could be wrong" in certain circumstances. That could impede a conversational act that was worth more than being epistemically humble or honest. And that could justify Plantinga-noncompliance.
Perhaps a test for when Plantinga-noncompliance is necessary is to say "Does the conversation end 'too soon' (in some sense of 'too soon') if an interlocutor doesn't violate Plantinga compliance?" An interlocutor dying or having to go to the hospital would interrupt the conversation.
The sentiment "I honestly believe if you step out into traffic you will die and although I could be wrong, I think it would be foolish for you to try.", if compressed into much fewer words, might combine humility with concern.