The smile of the contemplative in the presence of the Beloved is merely a physical expression of the total joy one perceives as one communes with God. St. Bernard used to say, "The joy of being in love is in the very loving." In other words, joy is not to be sought for itself, but is a by-product of love, and the smile is but the physical, exterior expression of the inner joy-love.
I asked the old couple what secrets they could tell me about living long and well. At first they looked at each other and laughed, then he declared,
"Things are as they are. I know my wife and she knows me. We don't hide from each other. We don't ask each other lots of questions, we aren't anxious, running around all the time. Everything is open between us. We say our prayers and do our work. Most of the day I am outside, and she is inside, and when we unite, we enjoy our company, thanks be to God."