Idiom - Take sth with a Pinch of Salt
Take sth with a pinch/grain of salt:
To listen to a story or an explanation with considerable doubt.
You must take anything she says with a pinch of salt. She doesn't always tell the truth.
They took my explanation with a grain of salt. I was sure they didn't believe me.
Persian:با دیده تردید به چیزی نگریستن، چیزی را سریع باور نکردن