How do you ultimately believe in the impossible in order for it to become possible? Well, you cannot. That is impossible! What a stupid question. You just cannot! So I return once again to what I have said above. There is no way of successfully persuading, convincing or forcing yourself to believe something. Put these meaningless cares to one side and get back to doing something more beneficial i.e. the process of putting one foot in front of the other in the direction of your goal.