What does "Exitus Acta Probat" mean?

http://www.washingtonsquareparkblog.com/2011/02/22/washington-square-arch-exitus-acta-probat-2/

The outcome justifying the deed that Washington was referring to was the Revolutionary war. No one wanted war then, not only was it near suicide for all who opposed the English, but also, war causes a lot of death which is also something that he didn’t want, however, if the end result was freedom and liberty, then a horrible deed such as war is in fact justified. It shows that Washington believed that unless the outcome is justified, then the deed should not be done.

I'd seen the painting of Cornwallis' surrender before, but had never seen the key that identifies the men in the painting.

Just sharing some historical tidbits I found while doing other research tonight.