It's no coincidence that J. Lo's ''Monster-in-Law'' bride-to-be wears a question mark around her neck. ''Her character is very uncertain about where her life is going,'' says a New Line rep. Hence the quizzical bauble, made of white gold and -- gasp! -- cubic zirconia. Certainly less bling than the real-life (and newly hitched) Lopez is used to. ''She doesn't wear it off the set,'' confirms the rep. We should think not.