Pour One's Heart Out Meaning

Example : 1852, William Makepeace Thackeray, The History of Henry Esmond, Esq., ch. 29:  He poured his heart out to them, so as he never could in any other company, where he hath generally passed for being moody, or supercilious and silent.1860, Nathaniel Hawthorne, The Marble Faun, ch. 7:  [S]he would be all the better for pouring her heart out freely, and would be glad to do it, if she were sure of sympathy1994, Rolling Stones, Out of Tears:  And I just can't pour my heart out, to another living thing, I'm a whisper, I'm a shadow, but I'm standing up to sing.2009 July 2, "Our Favorite Songs: General Colin Powell," Time:  The spirited lyrics, the dancing and the joy of watching these five handsome, clean-cut youngsters pouring their hearts out moved me then and moves me now.