Obviously don't put a young kid on Diamondback off-rip. But with someone 15 or older, going on Diamondback can be the best way to show them there really isn't anything to worry about on any of the coasters. Start them off on a kiddy coaster and their anxiety will be comparable, but then they might have the idea that Diamondback must be like 10x scarier since it's that much taller.
Also tell them Diamondback is the most technologically advanced and therefor the safest.