This seems to be a misstatement, at least on the literal level. “Christianity” cannot be broken or fractured. Wayward Christians (heretics, schismatics) have formed thousands of denominations, but the Christian Church, aka the Roamn Catholic Church, is unbroken. If Christianity means a body of people, then it is the Church, which is indefectible. If it means a set or system of beliefs, then it is the Faith, which is still one. To say “Christianity has broken” may reinforce the Protestant’s errors.

Just a suggestion, but you might start by saying that, sadly, Christianity has broken and fractured into thousands of Protestant denominations within the last 500 years. The Catholic looks upon this disunity as a tragedy, not something to be celebrated. When a person says they are a “Christian”, it could mean anything from Catholic or Eastern Orthodox to Lutheran or Methodist or all the way to the off-the-wall sects such as Mormon or Jehovah’s Witnesses. We call ourselves Catholic. The word “catholic” means “universal.” The Christian Church has been called “Catholic” since around the year 101 AD. We find the first written mention in history of “the Catholic Church” by St. Ignatius of Antioch who wrote, “Where the bishop is present, there is the Catholic Church” (To the Smyrnaeans 8:2 ). The second century of Christianity had hardly begun when Christ’s Church was already being called “Catholic.”
One major difference between Catholics and Protestants is their belief in the Church. (Catholic always use the word [C]hurch with a capital C and non-Catholic Christians use the word [c]hurch with a lower case c. Catholics believe that Christ and His Church are one. The Church is the Mystical Body of Christ. You cannot separate Jesus from His Church. He founded it in the year 33 and it’s the exact same Church in existence today. Christ is the bridegroom and the Church is his bride. They are one flesh in the same way that a husband and wife are the same flesh. Pope Benedict is a direct successor of St. Peter, the 1st bishop of Rome. Remind them that nowhere in the Bible does it say that scripture is the final authority in matters of faith. In fact, in 1st Timothy 3:15 it states that “the Church is the pillar and foundation of truth.” The Catholic Church was in existence 360 years before the New Testament was even fully defined. The New Testament is a collection of writings/letters to the early Catholic Church. Inform them that a book cannot interpret itself just as the U.S. Constitution cannot. That’s why we have a supreme court, for otherwise we’d have anarchy in the streets. The fact that there are so many competing Protestant denominations all believing different things based on their own interpretation of the Bible is living proof that it doesn’t work. It’s the perfect example of religious denominational anarchy.
When dealing with fallen-away Catholics, ask them if they really understood their Catholic Faith before opting to leave it for a denomination. I’ve talked to a lot of people on this subject an I can honestly say that I’ve literally NEVER met a Catholic who left the Church for a Protestant denomination who truly understood their Faith in the first place. If they did, they’d never have abandoned it.
There are many good and holy things about the various Christian denominations. They all have some elements of truth. The difference is that Catholicism (which is exactly NOT a denomionation, but rather “the Church”) has the fullness of truth. Invite them to study the Catholic Church from within and discover the fullness of truth. When studied with an open mind and looking toward Catholic sources instead of by authors and preachers who hate the Church, most reasonable people find that it all makes sense.

So I’d answer yes, because I accept Christ as Lord and Saviour every time I pray or recite the Creed. The fact that evangelicals might misinterpret my answer to mean that I share their view of “eternal security” is unfortunate, but would not deter me from answering thus. Of course, if they followed up the question with “So you know that if you died today you’d go to Heaven?” then I would, of course, set out the Catholic point of view.

I would appreciate if you would also share your explanation of what a Church really is.

It’s nexis is the profession that Peter makes to Christ saying that He is the Son of the Living God.

The church provides us you claim Christ as our Lord and Saviour every single Sunday. And to ensure that we have a fully developed understanding about God we proclaim that we know God as Three Persons Father, Son and Holy Spirit.

Then if their open I go into a bit of church history on how many Christians have witnessed (which explicitly isn’t just “claiming Jesus” but being martyred for believe in Him).

As a disclaimer however is that fact that I’m married to a baptist wife, so it’s apparently not that effective. But I think perhaps it’s like Jesus being unable to preach in His home town.

“I receive Him on my very tongue in the Most Holy Sacrifice of the Mass,” might be exactly the sort of hard-hitting response that would stand a chance of leaving an impression. In a way, it cuts to the heart of both the “errors” I mentioned without seeming pedantic. In the first place, it forces the question: “what does it really mean to accept Christ?” But also, by referencing the Sacraments, it touches on the other classic Protestant deficiency — the necessary role of the Church. I’m not saying that most of them would get all of this out of that one line. But the thing I’m trying to avoid in this situation is coming across as excessively dry and pedantic. I know (my experience with the Mormons taught me!) how easily that kind of thing is manipulated into “heart vs. head” kind of talk. I would like them to see that we Catholics have plenty of heart too, even if we don’t usually accost people in malls.

“More or less, yes. I believe that I have been saved (in Baptism), and I believe that I AM BEING saved (by sanctifying grace right now), all in hopes that I WILL BE saved (at the moment of death), should I endure to the end.”

Then, after a bit of discussion I would quote Gal. 5:24 at them “And they that are Christ’s have crucified the flesh with its affections and lusts.” and explicate it this way: “This indicates that those who truly belong to Christ have crucified THEIR OWN flesh. IT DOES NOT SAY that those who are Christ’s have invited Christ in to crucify their flesh for them. Therefore, those people who claim to be “saved,” but cannot say that they have in fact already crucified THEIR OWN flesh, regardless of whatever profession of faith they claim to have made, have NO HOPE of salvation contrary to what they might think about themselves.” Thereafter would follow a discussion of James 2 and how anyone who holds to Sola Fide in its litteral or grammatical sense must be a heretic, for he refuses to believe what the Scriptures actually teach, all in the name of preserving his protestant tradition. Be sure to spit that last word back in their faces to see how they react.

“I accept Him very personally every time I receive His Body, Blood, Soul and Divinity in Holy Communion. This is how He commanded us to accept Him, ‘Unless you eat my Body and drink My Blood, you shall not have life in you.’” This is one of the few passages of the Bible that Protestants don’t take literally.

I’ve only once dealt with being accosted by Evangelicals. It was in a mall. My friends all continued walking, but I stop for a moment to see what the crazy looking people wanted, and they open up with the ever so tactful, “If you were to die right now, are you sure that you would go straight to heaven?” I couldn’t help but grin when I responded with, “Of course not, sir. I’d have to spend a bit of time in purgatory first.” They hit me with another question or two and tried to get me to pray with them, but as my friends were waiting for me I was just trying to disengage from them. I can’t help but wonder if they ever get converts from this sort of “witnessing.” The whole thing just seems so uncouth.