I am not Catholic, nor Orthodox, etc.; I also do not agree with praying to Mary, the saints, or bowing down to statues, partaking in the sacraments that comes only from a church book (not found in the Bible), and nor do I believe in purgatory and yet, I believe that is the one of the few things the Catholic/Orthodox type churches get right is... that we are saved by God's grace and by Sanctification, too. For they also believe in the Trinity, right? Well, I also believe in the Trinity, as I am sure you do, as well.
Anyways, 2 Thessalonians 2 says,
"...God has from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth." (2 Thessalonians 2:13).
So it is not one or the other alone. One needs a belief in the Savior and one also needs Sanctification by the Spirit, too. This may be hard to accept because the belief you have is all you have ever known, but the Word of God cannot lie and it is plain in what it says here.