Innocence & Authenticity

Does authenticity matter in fiction? Do we need to believe in the truth of the characters and their behaviors to stick with or appreciate a novel? I think that my answer to this question is yes, at least me for me. If I can’t believe in the character, it is like watching a poorly acted movie. The suspension of my immediate reality never occurs, and I am never sucked into the book (or movie) in a deeply satisfying way.