Kodiak & Gonzo,
My wife started out like that. Fortunately, she loves me enough to indulge
me in random acts of goofiness. However, she is also pragmatic and understands that self defense is a necessity.
So she now has her own handgun, a S&W model 60 and goes to the range occasionally to keep up her skills.
She understands the need to have extra food, water, medical supplies and other necessities stored for an unexpected disaster.
I think Hurricane Katrina helped to open her eyes quite a bit.
Stay positive in conversations and promote the safety aspects of being prepared. It's really just common sense.
I'd also suggest keeping preps relatively low profile. A bunch of military gear and manly macho stuff will likely be overkill and that stuff may just turn her off the whole idea. (slow and steady wins the race
Ask her in terms of a Katrina or similar disaster, would she have rather been stranded or in the Superdome or able to ride it out in her own place of refuge?
Perhaps that will start things in a more positive direction.
Good luck, some preparation is much better than none, and mindset is an awful lot of survival.