Yes, good always win
There is a sutta, wherein the Buddha said any good action leads to good result, and bad action leads to bad result, there is no grey.
But if you think good always win with your own eye then you are wrong. E.g lets say there is a war, the winner win by a vicious manner over the good side. From the flesh eye, the good loses, but from the Buddha's eye, the good always win. The good side lost because they did bad kamma in the past, while the winner side did good kamma in the past that leaded them to the pleasure of winning. On the other hand, the winner side also did bad kamma in the past that throw them in the situation that they need to do vicious actions in order to win. Also, by doing bad action to win war, that will lead to bad result in the future.
There are two cases:
1/ The winner needs to do vicious action, that is the only way to win, e.g. war in medieval time. That is the kamma of both sides.
2/ The winner doesn't need to do vicious action to win, but they still choose to do it. This is the bad kamma of the winner in the past, which leads them to the ignorance of the present, and the bad result in the future. Also the bad kamma of the losing side makes the winner side to choose vicious manner.
In the end, good always wins. But the result spans over eons, not in this very specific life. So if good loses, because good was bad in the past. It is extremely hard to judge kamma from the present because there were infinite number of lives and actions in the past. Hardly all of them good or exhausted totally.
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