Correct

会心

/ huìxīn / 
Strokes

Definition

knowing (of a smile, look etc)

Example

As a Verb

understand what is implied/implicit in

1
Tā
他
huìxīn
会心
dì
地
kàn
看
le
了
kàn
看
wǒ
我
  
。

He looked at me knowingly.

2
Huìxīn
会心
de
的
wēixiào
微笑

understanding smile