There are event you can predict on that even though it's not 💯 guaranteed that you're going to win, a level of certainty makes you think that you're surely going to win.
Op can you at least explain to us about the event you're talking about Here? though you're right when you said about certainty because in gambling there is two things involve is either you win or you lose so this two things is very certain rather it takes a lot of time before we can experience wining that's depending on the method we are using to gamble, this is the reason why some people don't easily give up in gambling because they believe that some day that they will be lucky to win just like other people, this motivates most people to keep gambling without thinking of stopping whether they're in a losing streak or not they don't care.