A marketing hook or tagline is a 1-2 sentence statement that grips a readers attention when viewing your book and determining whether they want to read your book description and other metadata. It works in tandem with the book description, and should not repeat the same point you outline there.
This tagline should be short, succinct, and attention-grabbing. Best practice is to ask yourself what about your book would draw a reader in to learn more.
On cover designs, this tagline is either at the top of the back cover, or placed on the front cover.
For ideas and guidance, we suggest reading the taglines of books similar to yours on Amazon or at your local bookstore, these are called comparable (comp) titles.