I use the word "opinion" here so as not to offend non-Catholics.
This discussion boils down to proving several things, including:
1. The Bible's (especially the Gospels') authenticity
2. Jesus as God
3. The Catholic Church as created by Jesus (a visible church,
against which the gates of Hell shall not prevail)
4. The role of the Pope, as the successor of Peter, to whom
Jesus handed the keys of Heaven to bind and loose.
Unfortunately, I am not qualified to lay out these proofs. However,
there is a book called "Catholic Evidence Training Outlines", written
in 1934 (orig 1925) by Sheed and Ward, which outlines the arguments
for all of these proofs and gives sources for research. This book was
used by many street corner apologists of that era for training.
I don't know how out of date the material is, however. If there
isn't a current printing of it, which I suspect, you can obtain
copies from Loome Booksellers in Stillwater, MN (612-430-1092).
They are a world-reknown (sp?) source for out-of-date spiritual
books.
Sincerely,
Steve Stolz
steves@uccs.com
[ PS: There may be better sources. If so, sorry... ]