You have to have confidence in your ability, and then be tough enough to follow through.
你必须对自己的能力有信心，然后足够坚强地坚持到底。
The profession of book writing makes horse racing seem like a solid, stable business.
"No hay nada más peligroso que un hombre que no tiene nada que perder."
Psychological concepts must prove their worth in action.
"History is always written by the victors, but the voices of the defeated are equally important."