I recommend Proofs by Jay Cummings as an exceedingly gentle introduction of proofs. It's not as serious as your typical math textbook; it has plenty of jokes to keep you entertained. https://www.amazon.com/dp/B08T8JCVF1If you still want a gentle introduction to proofs but would prefer if the author uses a more serious tone like traditional textbooks, I recommend Proof and the Art of Mathematics by Joel Hamkins. https://www.amazon.com/dp/0262539799

An Infinite Descent into Pure Mathematics by Clive Newstead

99 Variations on a Proof by Philip Ording