I was wondering how as a Muslim have a better understanding of Allah swt existence. I want the have that certainty.

We must understand Allah with our hearts. Although it is not appropriate to ponder on His being or existence, we must recognize His right on us and see Him through His creation. According to a tradition, it is reported that we should know:
1. Know Him by understanding what He has done subtly (the things He does that we don’t even realize or sense)
2. What He has done with us (your own state)
3. What He expects from us
4. What takes you away from your religion