Well you all may or may not agree with me on this, but I will say it anyway...
You can never tell if ANYONE is telling the truth. Not with just HPs or just with NONs or another disordered person or even a crazy person. When you meet someone for the first time, are you the type of person to just naturally believe what they say??
EX: If a random person walks into a store and says they just witnessed a shooting on the way there to the store, and tells the details blah blah blah. Most people are inclined to believe such a story because who would make up such an awful story?? And another person walks in and says THEY just witnessed a shooting on the way there and tells THEIR VERSION of the story blah blah blah. Well it is likely that such an event took place, but you will however have TWO DIFFERENT ACCOUNTS of that story and depending on the people telling the stories of how similar or how utterly different it could be.
When the accounts are TOTAL differences and you think how could one person get it one way and the other get it so different? Well our emotional response is the first thing that filters in us before the actual reasoning so therefore as my husband always says, there is THIS PERSONS account, ANOTHER PERSONs account and the truth is somewhere in the middle.
I am not one that just believes any person just because they are having something come out of their mouth. And if I KNOW the person I sure take that into consideration whether I beleive ANYTHING out of their mouth. We have one woman at work that when she starts talking, most everyone on the side sort of rolls their eyes because no one believes anything she has said.
BUT everyone wants to believe that HPDs mostly lie more so than the average person. Perhaps that is true, but what HPDs do in life in general that lure in those around us, is no different than what most people do on a daily basis in the romance department of "fluffing up" ourselves to make us sound better than we are. this is HPS AND NONS alike. This is online, in person, on the phone, or on the street. Some might suck in their gut to make it appear they watch their weight, some may tell of a horrible story of their ex to automatically explain why they are either single or divorced, some may want to feel rescued by that "man" right away because they are a single woman, lonely, etc.
Look at mostly the online dating stuff and most of you probably know someone that has or have done it yourself. Probably you will find that most everyone "fluffed" just a little on their profiles. Mostly I can see the top item for lying would be weight and the next one age. They feel if they post a certain number on there, that automatically they will be ruled out when the search is narrowed for a certain limit.
Then relationship information is "fluffed",
Then financial or professional life is "fluffed" just a little.
Then probably racial, ethnic, or religious backgrounds mostly want to remain unknown until they can "meet" someone then let them get to know them before voicing these things. JUST SO they don't get RULED OUT of that NARROWED SEARCH.
SOO which means that millions of people "fluff themselvs up" to SOUND BETTER, LOOK BETTER, and BE MORE SOUGHT AFTER so that they can FIND A MATE.
This is similar to what HPs are good at yes, but lying is lying. A little white lie is no better than the full fledge malicious lie. But you will find that most HPs do not MALICIOUSLY lie. When they feel they are going to be painted unflattering, they tend to OMIT rather than lie first. Then if they absolutely have to they will LIE to not sound as bad or of course to get out of trouble.
Yes children do this too as we have pointed out that a lot of HPs are STUCK in that emotional immaturity stage of an adolescent, therefore they do a lot of the things kids do when caught in a lie. BUT, a lot of NONS do this too.
AFFAIRS?? the first thing out of the mouth of a man cheating on his wife is, THAT ISN'T TRUE even though there are texts, pictures, messages, phone calls to and from the number of the woman he is cheating with. He will INSIST he doesn't know that woman, never had sex with her, never knew her UNTIL all the EVIDENCE is laid out on the table in front of him to make him acknowlede SHE (the wife) KNOWS he had an affair. Then as with most of the more famous accounts in the media of affaris is HE BREAKS DOWN, has a true confessions time, and instead of just saying, I lusted after a woman wanted to sleep with her and did, and I am an awful person for doing it, All of a sudden that man has a SEX ADDICTION!! Well no offense men, but I don't know ANY MAN that doesn't have a sex addiction if that is what it takes for a man to lust after women to sleep with them. haha That is only SORT OF a joke.
Heck, I could say my husband is a SEX addict if that is the case because the second my shirt comes off or sometimes just cause he is THINKING about my shirt coming off, he wants me.

(just adding a little humor there)
It is NOT the same as the TRUE SEX ADDICTS that actually go for help. There are TRUE PEOPLE with problems, but it seems as though society has let us believe that because someone cheats they have an ADDICTION.
Not only HPS or disordered people have affairs.
My point being is in relation to the actual topic of this thread is how do you know if an HPD is telling the truth???
Well I say How do you know when ANYONE is telling the truth???
By the time you experience the actual "AHH HA" moment that something wasn't right, either in the HP or the Non, you pretty well have SOME TYPE of emotional investment in that person to even know if what they are saying is the truth. And you WANT to believe them and believe IN THEM. Who WANTS to believe right off the bat that a person tells you your beautiful that they are liying?? Of course you want to believe when they tell you they love you and will take care of you for the rest of your life. Who wouldnt'?
If we could see the very early redflags in people then there wouldn't be near the divorce rate that we have in this country.
We would have enough time to say, WHOOOA! STOP!! ABOUT FACE!! AND RUN!!!
Just my two cents.
S