We not only think, we also “want.” We look for what attracts us. The will is the faculty that gives us the capacity to “move ourselves” towards a good that we desire.
The will always looks for a good that has been previously discovered by our intelligence. The will “moves” to be able to achieve the happiness that our intelligence thinks we will receive once we obtain the good we desire.
So, just like there are “truths” and “Truths,” there are also “wants/desires” and “Want/Desires.” Wanting to eat a piece of chocolate at a given moment is a relatively unimportant desire. But to want to be eternally happy is a desire that can affect all of our thoughts and actions.