There is a limit to this reasoning, though. As the wagered amount starts to become a significant fraction of your wealth, you should not make the bet even on very certain matters. Because that's the way you go broke in the long run, even on very sure bets. (Expose yourself to a 1 % loss often enough and eventually you will suffer it.)

In other words, we might be "diffident" at the prospect of "staking the happiness of our whole life" but that does not mean that "our belief does not reach so far." It just means we are rationally evaluating the risk of ruin in the long run.