Math problem, the cost of Joy

In The God Who Weeps, I read, "If vulnerability and pain are the price of love, then joy is it's reward."
Here is how I compute this:
Courage + the pain of vulnerability"= LOVE. . . .= JOY
I have started to read another book that will show up on my referenced list, Some Miracles Take Time by Art Berg. Art writes about his rehabilitation after a car accident. I have thought while reading this that I do not have to write a book because Art has written his. I am grateful for others who have been through similar experiences and their courage to be vulnerable and share about their experiences. I have much to continue to learn and am excited to do it.