You can say exactly the same thing using completely different words.
However, that does not change the fact that belief and opinion have different meanings.
A belief is a state of mind in which a person thinks something to be the case whereas an opinion is a view or judgment formed about something. That is the difference between the two.
I have repeatedly shown you that they have basically the same meaning, especially in this context. I have provided dictionary definitions and working examples. I have even shown why those two definitions you use are essentially the same.
And yet, you ignore all that and just keep repeating the same refined claim, that "belief" and "opinion" have completely different, non exchangeable meanings. Whether this is through dishonesty or ignorance is anyone's guess. It is hard to believe that even the least capable person still can't grasp the idea after so many explanations, so it suggests that it is deliberate. But on the other hand, you repeatedly show a complete lack of critical faculties and rational thought, so maybe you really just don't get it?
What is the practical difference between
"It is my
belief that education should be free"
and
"It is my
opinion that education should be free"
"It is my
belief that Chelsea are the best team in the league"
"It is my
opinion that Chelsea are the best team in the league"
"It is my
belief that god exists"
and
"It is my
opinion that god exists"
And don't just say "they are different words". You need to explain why the two phrases convey incompatible concepts.
Just have a go. And try block out the little voice in your head repeating
"he must be wrong, he must be wrong, he..."