A belief is just that: something we believe. You can believe things for a number of reasons.
A “faith” simply means you stand by your belief, even if you don’t have all the answers.
For example, you can believe that going to college will offer you a higher paying job. (you don’t know this for sure, and in fact there are many wealthy people with little schooling.) That is a belief.
But to go to college, you have to have faith that your belief is right. You don’t know for sure it will happen, since you can’t see the future. So it takes a lot of faith considering the costs and time involved in doing it. Some people make more with college degree, some make way more without (famous people, models, actors, etc.). In fact, most of the very richest people in the world don’t have a degree.
The thing you have to keep in mind, is that at the end of the day no one (atheist or christian) can prove for sure that God does exist or God doesn’t exist.
We weren’t there at the beginning of time, therefore we must form a “belief” based on what we think happened. There is evidence for a variety of scientific laws and theories, this doesn’t mean God doesn’t exist. And there is also a lot of evidence for the existence of God.
So basically, everyone has “Faith” or “belief” since none of us were there. Many scientists (or atheists) “believe” that there isn’t a God. Many religious people “believe” there is a God. Neither can 100% open up a box and say, “See here is God, or See, God doesn’t exist.” There is no such thing as a piece of evidence that could prove God doesn’t exist.
Therefore, it all comes down to what you believe in life. Everyone is entitled to their own belief, and shouldn’t be criticized for it. I believe there is a God. Sure I have questions, and sometimes in my dark moments I have doubts as well. But it makes a lot more sense to me to have faith in a God, because even if I am wrong what have I lost? Nothing. But if I am right I gain everything.