Books
The joys of parents are secret, and so are their griefs and fears: they cannot utter the one, nor will they utter the other.
— Francis Bacon ‧ Of Parents and Children

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Parents keep their happiness, their sorrow and their worry mostly private. According to this observation, they can't fully put the joys into words and won't voice the griefs and fears. Feeling deeply and saying little go hand in hand.
Context reviewed