LONDON—A London police officer appeared in court on Saturday after being charged with the kidnap and murder of a 33-year-old woman in a case that has caused widespread outrage in Britain about women’s safety. The disappearance of Sarah Everard as she walked home on the evening of March 3 triggered a wave of accounts from women about the dangers they faced when walking streets alone at night, accompanied by calls for action. Kate, Britain’s Duchess of Cambridge, was among those who paid their respects on Saturday at an impromptu memorial that sprang up around the bandstand on Clapham Common in southwest London, near where Everard was last seen alive. A palace official said Kate, wife of Prince William, “remembers what it was like to walk around London at night before she was married.” Later on Saturday as night fell, around a thousand people—mostly women—gathered at the site to pay their …