Mass? He's not catholic - is he? I never heard that. Anyway, nobody knows another's heart like God does. God alone decides. And many of those who 'think' they are Christians, aren't. At least, according to Jesus and you know, He might actually know. In Matthew 7:23 he speaks of the last days when many will say, "Lord, Lord," and He will say, 'I never knew you.'

Also, it doesn't sound like these people really know their bible well. Look at the things David did, yet God called him a man after His own heart. I think He may view Potus in a similar vein.