GIVE ANSWERS - 官話

赤子之心："heart of an infant"，In the context, its meaning is: pure, passionate, kind, the people have deep curiosity, kindness, frankness and enthusiasm for the world like a baby .

Describe the kind-hearted, pure.sometimes it also means patriotic heart

well, the correct one in chinese suppose to be “赤子之心”. the directly translation is "heart of an infant". it usually to describe that someone has a heart that as pure as an newborn baby. it comes from one of our ancient books.

应该的是：赤子之心