Only you can fully understand you.
There is simultaneous melancholy and joy in this statement.
Melancholy because you will never be entirely understood. No one will know all parts of you. Even if you try to expose someone to the various facets of your life, only you will fully experience the life you live. On that vein, expecting someone else to fully understand you is ludicrous.
But there is also great joy in knowing that you are your own. Joy in the sense that you have complete independence. You are the owner, the driver, and the purveyor of your own happiness. Hold this with a sense of pride.