The sense of the verse is this, The inward griefs and joys of men's hearts, though sometimes they may be guessed at by outward signs, yet are not certainly known to any but a man's self. Compare 1 Corinthians 2:11. The scope of the parable may be to keep men from murmuring under their own troubles, or envying other men's happiness. A stranger, any other person without or besides a man's self, doth not intermeddle with his joy; doth not partake of it, nor understand it.
Related Commentaries of Proverbs 14:10
Proverbs 14:10
10 The heart knoweth his owna bitterness; and a stranger doth not intermeddle with his joy.