The Church has the promise that evil will not overcome her and remains true in that she still proclaims the moral law, to all her children.
But what about when it is the church doing the evil?  Clergy preying upon the weakest and most vulnerable, with bishops and popes protecting the predators so they can prey upon the flock for decades before being caught by secular authorities.  Jesus said something about whatsoever you do to the least of my brothers.  Under that standard, the church which will not be overcome and which "remains true" raped Jesus thousands of times, and continues to do so.  The moral law JPII and now Francis and many bishops proclaim is "don't get caught."