not have one’s heart in the right place

心术不正

She always has an ax to grind. You should take whatever she says with a pinch of salt.

她总是心怀叵测，对她说的话你得多留神 。

I was taken aback and didn’t think the Empress would stab me in the back. I placed too much trust in her.

我万万没想到皇后会在背后捅我一刀。我过去太信任她了。

I feel sick of her. She always speaks with her tongue in her cheek.

我特别讨厌她。她说话总是假惺惺的。