Proverbs 14:10 in the World English Bible
The heart knows its own bitterness and joy; he will not share these with a stranger.
Context
9 Fools make a mock at sin: but among the righteous there is favour.
10 The heart knoweth his own bitterness; and a stranger doth not intermeddle with his joy.
11 The house of the wicked shall be overthrown: but the tabernacle of the upright shall flourish.