The biggest indication of lack of faith is when you start being prepared for disappointment...
If you expect to fail in the end, can you put in your best effort? If you try to play safe to prevent disappointment in case something doesn’t work, do you think you can give 100% to the cause? And if you don’t give in your best, don’t you think that you have lesser chances of succeeding?
Battles are fought and won only when you have complete faith in the cause. Either you want to win or you don’t. If you want to win then believe that you will win. Otherwise give up right now and move on to something you really believe in…