Agree with Mutt, go mainstream with domains like that.
You COULD go XXX dating but the market is much smaller. However, I would also consider 'splitting the baby' here and choosing JewishGirls.com for the mainstream dating site and italiangirls.com for the porn dating site.
Besides dating of any kind I would also consider using those domains for 'Craig's List'-type sites, focusing on Jewish-related (or Italian-related) topics.
Last idea would be to do a Groupon-type site for JewishGirls.com and offer (mainstream) coupons, discounts, deals, etc. That could be killer.
Best of luck with whatever you decide to do!
PS: If you're commited to going adult with those domains then consider turning them into either escort sites or sex tourism sites.