I held back not knowing his real intention.

我有点犹豫不定，不知道他的真正意图是什么。

I wouldn't mind knowing his real intention.

我想知道他来的真正意图。

He told a lie to cover up his real intention.

他撒了一个谎以掩盖其真正意图。

Mask my real intention of going on an outing.

掩盖我要去郊游的真实意图。

A: I wouldn't mind knowing about his real intention.

我倒想知道他来的真正意图。