..If you think there is any salvation outside the Catholic Faith, you cannot save your own soul – even though you never told it to anybody! You cannot say: "I am not going to deny it orally, but I am not going to believe it inwardly."
You never could save your soul that way. You would be praying hypothetically. There would be a condition in your prayer, a proviso, a hold-back, a little limp in the wrong place. You would have a hidden suspicion in your mind that the Catholic Faith was not truly the way for you if you could have been saved without it in another situation.
If you think that people who live lives unmotivated by the true Faith, and who measure up to all that is best and sincere in themselves, get into Heaven by reason of that performance, it would take only the slightest bit of adjustment to see yourself as that person...."