Al-Qasas 28:10

Waasbaha fu-adu ommimoosa farighan in kadat latubdee bihi lawlaan rabatna AAala qalbiha litakoonamina almu/mineen

And the heart of Moses' mother became empty [of all else]. She was about to disclose [the matter concerning] him had We not bound fast her heart that she would be of the believers.

And the heart of the mother of Mūsā became restless; indeed she was about to disclose this (the real facts about Mūsā), had We not strengthened her heart to remain among those who have firm belief (in Allah’s promise).