You’re correct that a profession of faith is the only requirement, but I think what she means is it must be genuine. That many people who claim to be Christians in reality are not can be shown from God’s words, “I never knew you.”
That's correct.
I've met numerous people who claim to have *accepted* Christ who never showed any spiritual growth at all in the least, and yet, because they allegedly prayed a sinner's prayer and maybe had an experience in getting knocked down (or dropping) at a Pentecostal *revival* service, they are told they are saved.
One must confess with their mouth AND believe in their heart.
Sure, Jesus can heal you, give you lots of money, make your life great, want to accept Him? Who wouldn't for those kinds of benefits? And there were crowds who followed Jesus here on earth and heard Him speak Himself with their own lips, who followed Him only for the free food handouts.
But if you really don't see your need for Him and believe Him for SALVATION, then simply professing Him because it sounds like a sweet deal, I doubt is going to save anyone.
Mouth profession alone is not enough. The Pharisees professed to know God.