Whether is commonly used to express if with a sort of doubt. Ei according to the cambridge dictionary "whether is used especially in reporting questions and expressing doubts"
Eg I am not sure whether I am right OR wrong. I wonder whether I can do it [or not].
And sometimes, whether is rather used to express a kind of politness.
Eg I wonder whether I can borrow your book?
Not a teacher at all
Student or Learner