Living is an act of will. In fact, it is the most important act of will humans can express.
Loving is also an act of will. Genuine love is an act of will. Though we often think of love as emotion, and love can indeed be fueled by emotion, it is more than just feelings. It is willful decisions to act in ways that benefit another, even though sometimes sacrifices are required, and there may be no direct or immediate benefits to self.
Happiness results from acts of will. It is often a choice we make to enjoy, appreciate, be satisfied, content, or fulfilled. No matter what we have, or how much we have, we still must decide whether or not what we have is enough to make us happy. There are those who will to be happy even when they have few or no material things. Then there are those who have massive excesses of money, materials, and power, but are still not happy.
Happiness also results from what we do. Doing is an act of will. We often chose to do certain things because we believe they will make us happy and avoid doing other things because we think they will not make us happy.
Sometimes the things we do make us happy, sometimes they don’t. We then can chose to do what makes us happy and avoid doing what does not make us happy. These are acts of will.