He is a very valiant trencherman; he hath an excellent stomach." Valiant comes from the Latin valere. Based on the context of the excerpt, valere most likely means A. reliable. B. frail. C. strong. D. moral.
If one has a healthy stomach, that means he has the ability to digest many foods and will not become uneasy or queasy with such images as blood or other gruesome activity. So, he has a strong stomach.