Donald Trump missed a chance early in the presidential race to make inroads with independent female voters, but now the damage is done and analysts say the Republican front-runner likely can’t make amends with women he repulsed by spewing insults and sexist remarks. Republican presidential candidates have suffered a gender gap for decades, but Mr. Trump turned the gap into an abyss, which polls show will doom him to a sweeping loss in a general election matchup against Democratic front-runner Hillary Clinton. The real estate mogul fared worse than his two Republican rivals in theoretical matchups against Mrs. Clinton, largely...