Correct

私交

/ sījiāo / 
Strokes

Definition

personal friendship

Example

As a Noun

personal friendship

1
Liǎng
两
rén
人
sījiāo
私交
hěn
很
hǎo
好
  
。

The two of them have been close friends.

2
Sù
素
wú
无
sījiāo
私交

have no personal friendship at all