Yes!
Believing a claim because the claimant also claims it's true is logically redundant, no different from simply believing the claim. Presumably, you don't just believe all claims made in books, so there must be something more to it - perhaps it's an
appealing claim, you want it to be true; and/or it's a deeply
familiar claim (perhaps you've always believed it); and/or
a lot of people believe it; and/or people you
respect believe it; and/or it fills a
need, you'd feel lost without it; and/or it makes you
feel good...
I'm curious to know which of those, if any, you accept as contributors to your belief, and if you can suggest any others - because the idea that you believe something in a book,
solely because the book says it's true, is hard to credit.
My reason for probing this way is because I'm interested in why people believe the things they do, and whether they have the self-awareness to have thought about the reasons (as Plato/Socrates said, "
An unexamined life is not worth living"). Of course, not everyone
wants to understand why they do what they do, and not everyone wants to describe it to others...