Posters on here come in all shades of political and religious opinion, tastes in food, clothes and TV programmes, willingness to engage in debate or keep schtumm, ability to be tactful or not, just about anything they can differ about, but I can hardly think of any I would expect to tell deliberate lies.
Some like to wind us up from time to time when they are feeling mischievous, and some new "members" suddenly appear with an outrageous post and vanish even faster, but I think very very few are outright liars.
I frequently disagree with what is posted, (not that I always comment to say so) but as to knowing who to trust? I would trust 99.9%, and of those who took the trouble to reply to share their experiences undergoing medical tests with someone who was about to keep an appointment, I don't think I would "mistrust" any.