I heard a Catholic Bishop use the term, non-Christian Believers and thought it a bit of a contradiction. Believers are Christians; they just may not be Catholic.
Denominations have confused the simplicity of salvation through Jesus Christ. In simplest meaning, there are two groups of people that are found in every denomination, Christians and non-Christians; in other words, Believers and non-Believers; in other words, the Saved and the Lost.
“For by Grace are you saved through Faith and not of works, lest any man should boast.” If you confess with your mouth the Lord, Jesus Christ, and believe in your heart that God has raised Him from the dead; you shall be saved…for with the heart, you believe unto righteousness and with the mouth confession is made unto salvation.” Scripture upon scripture reveals the simplicity of salvation.
The concern is not whether one be Methodist or Baptist or Catholic or whatever other denomination, but whether one has accepted Jesus Christ as Savior and Lord.
I encourage you to read the 3rd chapter of the Gospel of John (verses 1-21) where Nicodemus asks Jesus, “How can one be born again?” The answer Jesus gives is the simplicity of salvation. The 16th verse gives the reason Jesus died on the cross.
Jesus answered, “I am the Way, the Truth and the Life. No one comes to the Father except through me.” (John 14:6 NIV)
Accepting or rejecting Jesus Christ will have an Eternal affect on your soul.
It is the only choice that really matters.