There is no 100% certainty in this world. You only have a probability.
So lets put it this way, if you were uncertain about something, then you would be dysfunctional because you wouldn’t be able to put weight on a choice that needs to be made (unless that choice doesn’t need to be made in which case you’d be a mute), so by default, any action you take is the result of more certainty than uncertainty and if, in fact, you do make a choice based on uncertainty, then you’re gambling with your life (as applicable). 50/50 it will be a positive outcome or negative one, or more or less positive/negative.
If you’re, for example, uncertain during a battle at war, you’re much more likely to be killed than someone who does not hesitate.