有信心未必会赢，没信心肯定会输 用英文怎么说啊

you will not always succeed within confidence,but will not without it.

May not have the confidence to win, not to lose confidence

You will never win for sure even if you have confidence, but you will surely lose if you have no confidence.

Having confidence may win or lose, but no confidence must be failed!

confidence will not determine your victory, but you could never win without it