1. 全心全意地：hear sb. out 听某人把话讲完 | heart and soul 全心全意(地) | heart and soul 全心全意地,完全地

2. 全心全意：by heart 牢记,凭记忆 | heart and soul 全心全意 | lose heart 丧失勇气,失去信心

3. 全心全意地,完全地：heart and soul 全心全意(地) | heart and soul 全心全意地,完全地 | heart to heart 坦率地

4. 心灵：head and shoulder头与肩 | heart and soul心灵 | heaven and earth天地

noun

1. the choicest or most essential or most vital part of some idea or experience

e.g. the gist of the prosecutor's argument
the heart and soul of the Republican Party
the nub of the story

Synonym: kernelsubstancecorecentercentreessencegistheartinwardnessmarrowmeatnubpithsumnitty-gritty