Knowing and believing are two different words that are often employed in religious teachings across the world. Knowing means that you possess knowledge of something, and you are sure of it. When many strict religious followers say that they know there is a God and he is loving, they will go to heaven.
On the other hand, believing something may refer to the belief in a certain religion or when they do not necessarily know something to be true, but they feel that it is. Belief is more rooted in deep emotion while knowing is more rooted in wisdom. If it was not common knowledge that the world is round, and someone were to tell you that the world is flat, you should not simply believe them.
It would be best if you did your research and investigation to find out the truth. While many people who are strict religious followers “know” there is a God, purely spiritual people tend to lean towards having a belief in God instead of presuming to know for a fact that God exists. Even if you have a strong belief about something, it should be tested to have a strong belief in knowing the truth.