Whether the stories themselves are really true or not I cannot possibly verify. However, when people submit stories to me (and they must do so through the template on this page or I won't publish them) they are told that by submitting them on the template they are in effect swearing that the story is true and that it is original with them. So if they are submitting false stories, they are breaking an oath. (Get more info about submitting stories here.)
Even so, I only use a fraction of the stories I receive every month. (I receive hundreds.) I choose them primarily based on how interesting they are, and also how well they're written, or how unique the experiences are. Many stories are rejected because they are relatively mundane or are similar to stories that have been told numerous times. For example, how many "old hag" (sleep paralysis) stories can I publish? They're all the same. Stories that are written in ALL CAPS or have absolutely no punctuation are automatically rejected because I don't have the time to correct or otherwise deal with them. Some stories sound blatantly made up, are derived from the latest horror movies, or are based on dreams. Those get tossed. So that whittles the number down to around 25 every month.
Thanks for writing, and I'd certainly consider your stories if you submit them through the template.