What is Elizabeth's proof that John is a good man in The Crucible?

Elizabeth knows that John is a good man despite his deceptive behavior and his affair with Abigail Williams (to which his deceptions relate). John promised Elizabeth that it was all over between him and Abigail, yet now it comes out that he was alone with her when she blithely revealed that all her talk of witchcraft was just "sport." John's infidelity was bad enough, but what really upsets Elizabeth is that her husband just can't be straight with her anymore.
Yet she will not judge him, whatever John might say—that's the job of the magistrate. Elizabeth has lived with John for years. For the most part, they've been very happily married. During that time, Elizabeth has come to know John very well indeed. And she must know that, whatever moral lapses he may have had, whatever mistakes he may have made, when all's said and done, he's still a fundamentally decent man. His innate goodness has undoubtedly been corrupted, but it's still there all the same.