Emuna is a choice.  It has nothing to do with being smart.  I know plenty of smart people who lack emuna.   It has nothing to do with seeing miracles.  The dor hamidbar saw the greatest miracles and still lacked emuna.   A person could have actual nevuah like Billam and still not listen to Hashem and lack emuna.  On the other hand, a person could choose to have emuna and see Hashem everywhere and in everything. ~ Based on a shiur from R’ Ephraim Lever