I had read this in Pema Chodron a long time ago and it rang true and was comforting. However, I was not able to feel this from inside and so I while I experienced moments of happiness, I was not happy. There was always a cloud over me.
Only I knew my true self was my heart, and I meditated on my heart embracing all aspects of my being did I suddenly know this. There is no more I can say; it just happened. See my post, "The Heart's Embrace."
If you are not yet at the stage of your practice where you are able to feel this truth from within, you can still derive benefit from this teaching. See my post, "We Have Everything We Need to Be at Peace and Happy Inside Ourselves."
Once we know, whether from within or from faith, that we have everything within ourselves to be at peace and happy, that the natural state of our heart is peace and happiness, we then form the intent to not allow anything to disturb that peace and happiness.
Forming this intent is of critical importance. Without that clear intent, without holding this at the forefront of your mind as you go about your day, you will not be able to work the next step successfully and free yourself.
After working the first step we knew that what we valued most was our peace and happiness. Now, we know that this is our birthright and will not allow anything to disturb that peace and happiness. And so we work the next step.