Optimism and risk
Do not be optimistic in the face of risk. You need to be honest, acknowledge, and share that you actually don't know the outcome. Why you may ask? Well, if you overcome the risk - when you overcome the risk - it will feel much more satisfying, less like something impending and more of a challenge you have overcome, a success, something notable.
I'm not saying to not be optimistic about risks; what I am saying is to not be optimistic in the face of risk. Do not stand up to it and give yourself an internal monologue like every cartoon super villain where you explain your whole plan before you enact it.
And, on the chance you fail; The pain wont hit as hard. It wont be the end of the world. You wont have to fall from cloud 9 to get to where you are now; and that is with a fresh mindset the has learnt something for the next time they find themselves in this situation.