[kosta50]

The LDS, the JWs and whatever other “cults” you’re referring to are not Protestant denominations and they are certainly not reformed

Yes, but by your definition that Protestants "are certain of their salvation because the Bible tells us if we have faith in Jesus Christ, we are among His children" includes all those cults for the same reason: faith in Jesus Christ. 

[Dr. Eckleburg]

Sorry, I usually write “Trinitarian Christians.” By that fact, the LDS and JWs are not orthodox Christians.