She agreed to help him 'out of the goodness of her heart'. [=because she is a kind and generous person]
He finally got a raise. 'Goodness knows' he deserved one. [=he certainly deserved one]
If you cook the vegetables too long, they'll lose all their (natural) 'goodness'.
(..) - You! - He's fine. - Did you just take his wallet? He took that guy's wallet. MARTY: Thank goodness. Great, Marty. As soon as I reload the fusion generator we'll meet on the roof of the school gym. MARTY: On the roof. -. LACKEY: It's him! (..)1989 Back to the Future Part II