I think this is an offhanded comment, but if you’re actually confused about the saying:
There’s varying levels of trust, if someone on the street tells you something bizarre, you’d probably be skeptical of it and not believe the information they told you.
But if your wife who you’ve been married to for 20 years and is generally a factually correct individual, tells you that bizzare information, you’d probably trust it a bit more and believe it, but its still a weird thing they’re talking about, so you’d probably want to verify by trying to find a news article or google the subject matter to make sure what they’re saying is true. Doesn’t mean you don’t trust your wife, just that the information they told you doesn’t sound feasibly correct, and you want to verify to make sure.
If someone with a PH.D in the subject matter tells you that weird piece of information, you’d probably trust it on the spot, but you also should probably verify with a peer reviewed journal article, just to verify.
Example in the context of your example:
a random person on the street stops you and says your wife is cheating on you. “Wtf? What do they know about me or my wife, I dont even know this person, they’re crazy…”
A good friend tells you that you’re wife is cheating on you. “Oh shit… Could she really be cheating on me? I should confront her and find out the truth…”
The guy your wife is cheating on you with, tells you your wife us cheating on you. “Fuck… This can’t be can it?? Fuck! I should confront her and find out the truth…”
Trust, but verify.
…not with this administration…