In CA, domestic violence is a valid reason to break a lease, so you may be required to let her out, though it sounds like you're okay with her moving out anyway. 

if there is a domestic violence issue with them ( u feel threatened) it might help in some way getting them out. document all your stress and aggravation and of course incidents. be safe! 

http://chicagoeviction.com/2013/01/refresher-on-ev...Domestic violence/ Elder abuse:http://www.illinoislegalaid.org/index.cfm?

Then a credit and criminal for her to make sure she's been taking care of her previous residences (no collections, judgments, domestic disputes) .

The story is that she moved out a year ago on a boyfriend due to domestic violence.

In these communities, the landlord must state the reason for the termination, and the reason may be reviewed by local housing authorities.207 However, incidents of domestic violence may not be used as a violation by the victim or threatened victim as good cause for the landlord to terminate the tenancy, occupancy rights or assistance of the victim.208The landlord must give the tenant a three-day or 30-day or 60-day notice of termination under California law (see "Written Notices of Terminations"), and both the landlord and the tenant must give the public housing agency a copy of the notice.209 What if the landlord simply decides not to renew the lease, or decides to terminate the HAP (housing assistance payment) contract?

The thing is, any kind of domestic disturbance situation can pose an element of danger to either tenant and others who get involved (for example, complain about the noise).  

There are, however, statutory provisions that allow for the voiding of leases (in most states) where there is some allegation of domestic abuse/assault/cruelty.  

I would consult with a local attorney to discuss the legal ramifications of entering into a lease with a domestic partner, and the ways a lease can be voided under certain facts should they happen.

So HUD wants you to actually use some common sense and understand there is a difference between someone arrested for shoplifting 20 years ago, or someone who was caught with a little bit of marijuana and distinguish that from someone who say is convicted of domestic abuse, armed robbery etc.