The writer speaks of the heart as if it were the part of the body that thinks. Your language may use a word other than "heart" to talk about the part of people that thinks. AT: "their inner, secret thoughts" (See: [[rc://en/ta/man/translate/figs-metonymy]])
The writer speaks of the heart as if it were the part of the body that feels sadness. Your language may use a word other than "heart" to talk about the emotions. AT: "he was very, very sad about it" (See: [[rc://en/ta/man/translate/figs-metonymy]])