Only God can see our hearts (1 Samuel 16:7). Only His Word can determine our genuine thoughts and motives (Hebrews 4:12). God in His omniscience knows everything about us, and sometimes it is necessary to ask Him to reveal to us who we really are (Psalm 139:23-24).
But unlike God, man can only know who we are by the outward manifestations of our character. Galatians 5:22-25 says that people who live and walk in the Spirit are characterized by certain fruits. It is by these visible fruits that others know us, and the people closest to us will especially know who we are by the fruit we produce.
A fruit tree is known by the person who planted it even before fruit begins to appear on the tree. When a tree bears fruit, people at a distance can get an idea of what the tree is like, but they may not have a full understanding. But the people closest to the tree know exactly what the tree is because they can clearly see its fruit.
What kind of fruit am I producing?