You are not saved until you are judged. If you believe, chances are that you will become suffciently merciful and pure in heart by the time you face the judgment that you will be saved when God judges you after death. If you don't believe, chances are that you won't.
God knows who believes as lip service and who believes in ernest and tries honestly to follow Chirst even if one honestly fails.
I would disagree.
One becomes a regenerated child of God by the indwelling of the Holy Spirit.
"Whoever believes in Him shall not perish."
"If we confess with our mouth the Lord Jesus and believe in our heart that God raised Him from the dead we will be saved."