そのひと　That person

その人の使う言葉で
In the words that person uses

その人の優しさが分かる
I understand the kindness of that person

その人の顔の表情で
With the facial expression of that person

その人の人柄が分かる
I understand the person's personality

その人の行動で
With that person's actions

その人の本質が分かる
I understand the essence of the person