By abandoning evil, and cultivating good, which the Buddha states are achievable goals, well-being and happiness are a result.
I have always thought the Buddha eschews terms such as “evil,” but not here. It seems as if that’s a general misconception, from my years hovering around Buddhism, but it may be "morally relativistic me" making that assumption. The notes point out that humans have a strong potential for evil, which can be arrested before action is taken, which is our choice, and our power of choice can be strengthened by the cultivation of good.
Even more simply, though we have evil desires, if we are doing good things all the time, we are more able to not realize evil intentions.
At the very least, we will have less time to do evil.