No matter how much we gain, because of karma we will never feel happy or satisfied, we will either want more or be in fear of losing what we got, so how exactly does a saint gain full content and happiness in life, since everyone has karma
Karma is only cause and effect, it brings the results of actions, nothing more or less.
Dissatisfaction occurs because of the ego. If the ego is removed, the consciousness is liberated.
The very nature of the consciousness is happiness. It needs nothing to be happy; it is just happy, by being what it is.
Therefore, we need to eliminate the ego.
Real happiness has nothing to do with "gaining" or "losing."