Yaqeen is being certain that Allah Almighty is in control of everything. Certainty is one of the main principles of Islam. It is knowing that nothing is beyond Allah’s control, whatsoever, even if we don’t understand the underlying wisdom is the bedrock of Islam.
Nothing should shake your certainty of Him. The moment you feel your yaqeen has been shaken, then there’s something wrong in you – something wrong between you and Allah, something wrong in your action, something wrong in your understanding. I have come across this many times, especially in the last 7 years after the so-called Arab spring. Many people’s imaan just collapsed with uncertainty. Their imaan plummeted and they left Islam