Finishing the מאמר, we use the new understanding of שמחה and ביטול to explain the זהר on the פסוק of שרה's life:

The reason why שרה was able to own her life was because she was an embodiment of true שמחה as it comes from ביטול.

This is the lesson - and the empowerment! - to us all: Through ביטול, we can express our joy, we can feel our joy, and we can enjoy our joy, always connected to Hashem!