from what i understand, this game has a dice roll mechanic, ie, each time you make a choice there is a randomizer that gives you random number
in the end you get 'your stat + dice roll number = the number that game checks in order to see if you pass or no'
for example: you need 15 to pass, you have 10 as your stat, you roll 6, you get 16 points, you pass the check. if you rolls less than 5, you fail the check
it's intended this way
but like developer said: failing doesn't mean losing, passing doesn't mean winning. either passing or failing a check will lead to different content. so always passing checks will make you miss out on certain content that might lead to alternative endings/variations of scene.
if you really want to pass check that badly, i recommend saving right before check and restarting until you pass it