The product is guaranteed to be reliable by 10 years of use by the military.
I can't think of a word or phrase we can use and that means something along the line of "guaranteed to be reliable". Even in the example above, the phrase makes little grammatical sense, because of the "by", but I swear there's a word or phrase you can use to fill in the blank.
The product is ____ by 10 years of use by the military.