In this context, at least, the prior distribution encodes everything - there's no meaning to the idea that you're more or less confident in the prior, because the prior already represents your uncertainty about the outcomes. If you were 50/50 on this prior versus another one, then your actual prior would be the average of the two.
There is a subfield of statistics that deals with imprecise probabilities, but that's a whole other can of worms and doesn't really relate to this problem. That said, it's fascinating stuff, and very useful in some contexts (if you're uncertain about your priors, it can be useful to do sensitivity analyses to figure out exactly how the end result depends on your prior).