A strong will is about continuing to want even though you don't get what you want. But also to move to a completely new will. It is the ability to put the better before the worse. A strong will is going to manage its emotions and still achieve results. Maybe have to think a little bit because it didn't go as planned. But the goal is still achieved.
A strong will is something you act on. A strong will is what drives us forward. A strong will is crucial when there is a crisis. The basis of will is why? Where the answers lays in beliefs, values and facts.