Nothing in life is certain, apart of course from uncertainty itself. No one has a crystal ball, and no one can tell the exact outcome of the choices they make. If you cross the road, you don’t know for sure that you will make it safely to the other side. In fact, crossing the road carries a fairly high level of risk. It is safer than going in an airplane, for example.
Yet this is something most people are comfortable doing on a regular basis. If you get on a bicycle for the first time, you risk falling off; chances are, you probably will. However, this risk carries a gain, the ultimate pleasure of being able to ride a bicycle. The risk was worth its reward. You could classify this as a low-level risk. While you might sustain a few scrapes, scratches and bruises as you learn this new skill, you know you are unlikely to die in the process.