Sentence:  As for this rider , I never saw him before or afterwards and never saw him dismounted , so whether he stood tall or short in his shoes , I can n't say ; but I do <WSD>know</WSD> that he gave the day tone and distinction . 
Meaning of the word marked with <WSD> tags:  be aware of the truth of something; have a belief or faith in something; regard as true beyond any doubt