That's literally how you beat polygraph tests. You believe the lie you need to tell, it is your truth.
Because for most people, lying causes anxiety which gets picked up by the polygraph but for a small percentage they have no problem with lying or believing a lie is a truth.
Yes that's why I can understand and relate to Jinsol. I've never been caught lying by polygraph tests because I make myself believe that what I said is true, even though it's not. I didn't know it's hard for other to do so hahaha I assumed everyone could lie and not get detected, but literally only me of 55 people who took the test didn't get caught.
It usually takes a certain type of personality such as psychopathic personality or other personality disorders.
But there are ways: https://www.livescience.com/33512-pass-lie-detector-polygraph.html
I don't think I'm psychotic. But I did grew up in an abusive household that I became indifferent to lying and somehow made myself believe whatever I say to cope with it, even tho it's blatant lies.
Psychopathic personality doesn't mean psychotic.
https://www.psychologicalscience.org/news/releases/psychopathy-a-misunderstood-personality-disorder.html
It has to do with emotional distance (empathy issues) and compartmentalization.
https://www.cbc.ca/doczone/m_features/psychopaths-top-10-and-bottom-10-professions
Hmm.. I don't think this trait (being able to lie) should be categorised into just one group of people. I, for instant, am empathic, tho I use it for my advantage as I know exactly how the other person would feel. Sometimes I use it to sooth them, but I do have times when use it to manipulate them. I read the articles and most of it are described as "lack of empathy". I can feel empathy, but I use it to manipulate people. I know I'm fucked up haha, but it's something I picked up from mt upbringing. This "ability" that I have is more or less a coping mechanism or a tool of survival for me.
This is exactly my theory. It's implied that Jinsol is disabled in some way, I think the mother said something about not wanting him to think of himself as disabled. I think he's a truth, but the thing is that his truth changes very very easily, and you put it perfectly. He can pretty much convince himself of what he feels because his feelings are wishy washy. Jinsol is intrigued by Saegye, and believes at this moment that it's love. At this moment, he thinks he'll stay together with Saegye forever. He wants to. But that want easily changes. Just like how he was interested in Chang oh for a short while and then left once chang oh got boring.
Thank you for the extra trivia, I love the fact that the Korean title lines up with their names! That's amazing.
This manhwa is so good. To make things even more interesting, the url for this manhwa is "honestlylying" on Lezhin and Saegye said "nothing spoils faster than the truth" (truths don't last), plus the quote from the book that Jinsol was reading says "you can only tell the truth, but the truth can change anytime". It pretty much indicates that Jinsol could be manipulating everything by desiring them at that moment (making them true) but can easily alter his emotions to do something that contradicts to what he said later on. It's very interesting because this is basically how human emotions work. Like one night stands? You can be "lovers" for that night and mutter words like "I love you" but act like complete strangers the next day. Even if it's just lust but the emotions you have for your partner at that time was real and you did "love" them momentarily during the heat of moment.
So basically Jinsol is a truth, who can manipulate his natures and thoughts.
Also, I learnt this from someone else but the korean title for this is "a truthful world" 진솔한 세계 (jinsolhan saegye), which is basically all of their names. Agh, the author is too powerful.