Unwavering confidence

I asked my dad if he thought he might regret putting all his life savings in btc and he just said “nope.” I don’t need any convincing about btc but I’d be lying if I said it doesn’t cross my mind at least sometimes that everything I put into bitcoin might evaporate into thin air one day. For those of you who really have absolutely no doubts, what helps you be so certain that you’re doing the right thing?