A movie or book can address a serious, emotionally wrenching subject and still be a thing you can’t help snickering at, a dramatic pileup that leaves you muttering “Oh, come on!” under your breath. It Ends With Us, the film adaptation of Colleen Hoover’s ferociously popular 2016 novel, works hard to ping all the appropriate notes. This is after all, a story of domestic abuse, a more widely shared experience in real life than most of us want to face up to. (Hoover has said that the book was inspired by her mother...