tonight's NCIS episode...
There are a few possibilities regarding Hannah...
* she's exactly what she seems - someone with an interest in Ziva & asked her out
* she's using Ziva to cheat on her (Hannah's) boyfriend/girlfriend/fiancee/spouse
* she's a honey trap to ensnare Ziva (Mossad used the tactic to capture whistleblower Mordechai Vannunu(sp))
* she's hoping Ziva will set up a date with her (Hannah) and DiNozzo (s1 Tony would've loved that - now? not sure, given that he won't like seeing Ziva disappointed/hurt)