Why would he say this if it wasn't true at this point? He has no motive to pander to evangelicals anymore. He already won the GOP nomination.
Well we don't know what he said, we just know this is what James Doddson interpreted from talking to Trump. No other evangelicals who were at that meeting have said this. Maybe Trump revealed a profound spiritual awakening to Doddson, and he has truly accepted Jesus Christ as his personal Lord and Savior and will now dedicate his life to the glory of God. Or maybe just maybe Trump tried to fit in and Doddson heard what he wanted to hear.