I am very of my beliefs relating to the philosophies I ascribe to. Many have withstood the test of time and will continue to do so hopefully producing many insights into both the nature of man and increase the knowledge of the universe at large. I presume you mean spiritual beliefs but sadly I don't have any.
Am I sure of my beliefs? I do admit I'm still a little confused about what I believe and what humans in general should believe, about life, about God and about meaning. But I'm fairly certain that one of the things all humans must believe (to make life enjoyable) is that we have a responsibility to maximize happiness in the world and to find ways to establish peace and tranquility. There's all sorts of ways of going about this, but it does require us to take actions with regularity that will benefit others.
I guess you can say the only belief I'm certain of is that we should act to increase the overall happiness and peace in the world. That's an essential philosophy for any life-affirming world view.
When it comes to religious/spiritual beliefs, people seem confident that what they believe is true. A majority of the world's population believes in a supreme being one way or another because it's a comforting thought, I'm not saying it's irrational to believe in God. There have been briefs moments when I asked myself this question: Do people really believe what they say?
To believe in something it must meet 3 qualifications. History, Experience, and Pure reason. We believe Roosevelt was the president during WW2 but we never saw or met him. So, to believe something doesn't make it true. There are basic philosophical truth qualifications to make something true. Certain things we believe in are not true and never will be.
While I firmly believe that God exists in some manner, we as people are incapable of knowing with certainty whether or not our spiritual beliefs are accurate. The majority of the world believes in some variation of God, but only death will reveal whether or not these beliefs are founded in the afterlife. Likewise, those who disbelieve in the supernatural can never be certain that there is no spiritual deity. We, as humans, cannot prove or disprove our spiritual beliefs, which is why every spiritual stance or non-stance requires faith.
People say they have a relationship with god but they are completely different morally and otherwise than other people who claim to have a relationship with god. Even people who believe in the same god are totally different . And every religion contradicts every other religion. But the people who believe in them claim to be certain that they are right when they have less than a 99.9 percent chance to be right as there are more than 1000 religions. Its ridiculous.