I "believed" in (known) God with the first dreams I had as an infant. I brought that with me to this lifetime. It has been an attitude and knowledge that has been cultivated for thousands of years.
It's like the difference between someone who is color-blind and one who can see all colors clearly. Pretty frustrating for the color-blind person. They may even feel, at times, that everyone else is playing a cruel joke on them -- that such things as color differences don't really exist. For those of us who can see, this is not an issue.
Because of this knowledge (not belief), miracles are possible.
The more we are like God -- loving, lack of self-concern, fearlessly confident, humble and perfectly responsible, the more effortless things become.