Before I proceed, I want to note that I have great respect for the Catholics that I know. They hold true to Biblical virtues and behold the same Word that we evangalicals do. My grandma is a born-again evangilical who prefers to attend her local Catholic church. In NO way am I accusing Catholics of anything at all. I respect them and consider tham one of the other fractions of "Christianity".
Having said that, here is my question: How do you try to ensure a Catholic is saved? It is the most difficult point of Apologetics for me. How do you find out if they are one of those "Catholics" that you can expect to see in Heaven or if they are one of those that aren't truly saved? How do you find that and how do you convince them that they need salvation? What arguments might they use against your analogy or testimony if at all? Can anyone go in-depth? Links? Books?