You can read my mind, and thereby tell what would surprise me? You have just claimed you can anyway. It is possible to "believe" in poetry? - I could argue that it is in a way, but I would love to see how you think it is done. Feel free to explain what you think "believing in poetry" involves.
Let's look at a definition of art that I've pulled from the net:
the
expression or
application of human creative skill
and imagination, typically in a visual form such as painting or sculpture.
The "form" can have a presence in reality, such as in the form of Braille. This isn't a subjective matter, Braille simply is as it is. A statue is made of a material that simply is as it is. same with a painting.
Poetry, could be written in braille or on paper. These are physically real entities that can objectively exist in observable ways.
The expression, the poetry itself, constructed with use of ones imagination, might read "it is the east and Juliet is the sun". This would be the subjective part that isn't actually based in physical reality. And immediately we recognize the subjective nature of it. Juliet is the sun? What does that mean? People unfamiliar with the popular play
Romeo and juliet could quite easily be confused by such a statement.
And so the belief comes with the perception of what the expression means.
And people do not perform scientific tests on whether or not Juliet is the sun. Rather its meaning is purely in the mind and is up for interpretation in different ways. It is an imaginary construct.
Now Juliet may literally be the sun. There may be a literal truth behind the words that resulted in their writing. But the words themselves, are just words. Words on paper or words on braille. The rest is in our imagination and could differ from person to person.