This attribute was pointed out by many Republicans.
When he lies, he thinks he's telling the truth.
No matter how pro-Trump you are - or anti-Democrat - shouldn't Trump do this?
Why doesn't M.Pence or M.McConnell, or P.Ryan, or R.Priebus, or, S.Bannon, or Melania, or Ivanka, or Donald Jr. or Erik Trump, or J.Kushner tell Donald the following:
1- lying all the time leads to people, including your friends and enemies, NOT trusting/believing you
2- you're the president - whatever you say will be fact-checked a million times
I suspect that he is in fact not listening. He really believes he knows more than virtually any Subject Matter Expert. Thats why with few exceptions he surrounds himself with highly inexperienced people with no background in governing, policy development etc. Steve Bannon, a guy who was long ago an investment banker but more recently was CEO of breitbart news, which is not a serious news organization but who now directs Trump through debacle after debacle. Jared Kushner, rich kid, but completely inexperienced in government as a senior advisor. They are totally in over their heads.
I'm quite certain he's been told many times. He just can't help himself. It's part of his pathology! He just doesn't care!
This attribute was pointed out by many Republicans.
When he lies, he thinks he's telling the truth.
March 20: Clearly mischaracterized the FBI director and Director of National Intelligence’s testimony about Russian involvement in the 2016 election
The NSA and FBI tell Congress that Russia did not influence electoral process.
— President Trump (@POTUS)
That isn't a lie. Russia did not effect the ELECTORAL process. Everyone in the government agrees on that. Did they fly over and vote?
Feb. 16, 2017: Lied about winning the most Electoral College votes since Ronald Reagan.
That's a lie.
Feb. 12, 2017: Falsely claimed that Bernie Sanders was cut off from CNN for using the phrase “fake news.”
While on FAKE NEWS @CNN, Bernie Sanders was cut off for using the term fake news to describe the network. They said technical difficulties!
— Donald J. Trump (@realDonaldTrump)
Sanders was cut off. Right? He can or they can say what they want. He said fake news and was cut off.
That is factually correct.
Feb. 10, 2017: Claimed without evidence that “thousands” of people were bused across state lines to vote.
Can they PROVE that it didn't happen? Of course not. Was it dozens? I mean that asshat was caught on video saying that they do it.
Feb. 9, 2017: Lied about Chris Cuomo not asking Sen. Blumenthal about him falsifying his service in Vietnam
Chris Cuomo, in his interview with Sen. Blumenthal, never asked him about his long-term lie about his brave "service" in Vietnam. FAKE NEWS!
— Donald J. Trump (@realDonaldTrump)
At some point, and was it after the tweet? Buzzshit doesn't say when he asked the question. They time lined everything else, why didn't they time line when he asked? Did he ask after the tweet. I can't tell.
Did he ask him directly about his service? Did he ask it in a way that it would be addressed? Nope.
Feb. 7, 2017: Claimed he was facing a historic delay to get all of his cabinet nominees confirmed
It is a disgrace that my full Cabinet is still not in place, the longest such delay in the history of our country. Obstruction by Democrats!
— Donald J. Trump (@realDonaldTrump)
Trump’s words: The same day that Trump’s education pick Betsy DeVos was confirmed, he tweeted that it is a “disgrace” that his “full Cabinet is still not in place” and that the delay is the longest “in the history of our country.”
It's certain that the D's delayed everyone at every opportunity they go. Was it "in history" probably not, but he still has a few not confirmed. Is it "in history" now?
Feb. 7, 2017: Lied that the murder rate was the highest in 45 years
In 2015, the murder rate rose 11 percent, which was the largest one-year increase in 50 years.
A lie? Yes. But it was the largest percent increase year over in almost 65 years...
On and on. I'm done.
The thing is when your hatred is so deep you look to zero in on every statement that he makes. You dissect every word. You take every work literally.
It's not like Adam Schiff doesn't lie regularly ether. What about Schumer? Piglosi? They all lie.
Focus on policy. Fight that policy if you can. The truth is your party has zero power right now, so all they have is to pick at his loose lips.
All of these lies didn't hurt a single America. Unlike a few of Obama's whoppers.
Do you really believe we would have gotten honesty and integrity from Hillary?
We got what we got and he aint gonna change. We had two bad choices.
Does ANYONE not agree with that?
You really want to stack up the Trump's lies against Hillary's. You want to stack up Trump's transparency to Hillary's. The Clinton Foundation underwent numerous audits, two of them forensic. There were no audits for Trump's because it was not registered, making it non-compliant with New York State law. We knew her financial information, not Trump's. Face it. You went for a pig-in-a-poke, and you got the pig. You can hate Hillary, but we knew much more about her, through the degree of transparency she demonstrated vs. Trump who tried, and did hide everything that he possibly could. 
That should not be confused with BrokeBackStabber who is a fat pig and likes to get poked
"Buying a 'pig in a poke' means that you got fooled or scammed because you didn't look inside the bag." Though I would argue that many Trump voters did not, and did not want to look inside the bag, as in thoroughly consider all his baggage! They were much more motivated to look into the bag relating to Hillary. Given that, there are more and more of them feeling like they got a 'pig in a poke,' and in this case getting a pig is not a good thing! )
You still don't completely understand what the idiom means. Or are you just being matt?
A bit defensive are we?
The CF is the least of my concerns re: Hilary's dishonesty,
Hillarys lies about Benghazi, stealing valor and her server are far worse than any of Tumps lies but I would acknowledge Trump lies more.
Again, you can twist yourself into a knot to try and tell me Hilary is more pious than Trump and apparently you need that to sleep at night and justify your vote but she is, was and will be a total POS, JUST as Trump is.
I can admit my guy is a horrendous liar. Wake me when you have the courage to do the same about your gal.
If you get any response from StMatt regarding a leftie lying at all, it will either be a deflection, parsing of words, or he will demand you answer ten of his questions before ever even acknowledging even one of words, to which he will NEVER give a straight answer to of course.
This clown could not run a preschool let alone a government..
We have NO evidence Donnie can't run a pre-school.