There are secrets of the mouth and secrets of the heart.
Most secrets are secrets of the mouth. Gossip shared and small scandals whispered. These secrets long to be let loose upon the world. A secret of the mouth is like a stone in your boot. At first you’re barely aware of it. Then it grows irritating, then intolerable. Secrets of the mouth grow larger the longer you keep them, swelling until they press against your lips. They fight to be let free.
Secrets of the heart are different. They are private and painful, and we want nothing more than to hide them from the world. They do not swell and press against the mouth. They live in the heart, and the longer they are kept, the heavier they become.
… it is better to have a mouthful of poison than a secret of the heart. Any fool will spit out poison, but we hoard these painful treasures. We swallow hard against them every day, forcing them deep inside us. There they sit, growing heavier, festering. Given enough time, they cannot help but crush the heart that holds them.
– Patrick Rothfuss in Wise Man’s Fear