If we knew it all, Jesus would not have given us the Church as our guide, nor would He have had to promise to remain with it. He would not have promised the Holy Spirit to guide the Church. The Catholic Church has stood by the promise of Jesus, rather than the confusion of Protestantism, where everyone decides for himself what God means in the Scripture, we listen to what He says by listening to what the Church which He founded and authorized, and guards says.
If I thought you where not really seeking the truth, I’d not reply to your questions, I would also not offer the links to other sites where you can find out more than my limited knowledge and typing skills.
In that vein, here are some short audio answers to the typical Protestant Charges against the Catholic Church….