- Will be willing to confess that belief to others to some degree
A true Christian's faith cannot be a private matter?
- Will believe that the Bible (both testaments) is infallible
A born-again Christian who accepts Jesus as Lord and Savior but believes the Bible is not infallible is not a true Christian?
- Will keep Jesus's commandments and many of the Old Testament commandments, especially the Ten Commandments
So a true Christian becomes a false Christian when he breaks a commandment? What happened to forgiveness of sins? Jesus died for our sins. If our sins cannot be forgiven then Jesus's death on the cross was in vain.
It seems to me that a true Christian is someone who accepts Jesus as Lord and Savior and who commits himself to following the ways of the Lord. How well they follow the ways of the Lord is another matter, and I think what you're really talking about is criteria for determining the goodness of a Christian, not the authenticity. This "true Christian" stuff is just a convenient escape hatch Christians use to disavow or disassociate themselves from misbehaving or embarrassing, but true, Christians.
--Percy