Entering into silence is like stepping into cool clear water. The dust and debris are quietly washed away, and we are purified of our triviality. This cleansing takes place whether we are conscious of it or not: the very choice of silence, of desiring to be still, washes away the day's grime.
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.