This statement means that if you are really determined to do something, however difficult it might be, you will find a way of doing it at last. The point is that you must have the will if you are to succeed.
Ninety percent of the failures that occur are due to the fact there is no strong will. Many people simply say that they want something, but they do not make any attempt to achieve it. Thus, instead of getting it, they use the weakest excuses to explain the situation away.