Broke up with Fiance 5 months ago, just kicked her out. Need advice

[2000Pimpinex]

With all the girlfriend topics lately, I thought I would post mine and see if anyone has advice. My fiance and I were dating for 2 years. I broke up with her because I didn't think the relationship could go any further. Besides that, we were having some problems that didn't seem to ever get resolved. I couldn't overcome our differences so I decided it was best to end it. I continued to let her live with me until school was out. That was a mistake!! 2 days ago we talked and I told her it would be best to go back home so we could both move on.
Its kinda hard to start a new relationship, with your ex living with ya, still. Ok, still following along? I was trying to hook up with a girl while all of this was going on. Mistake #2. I should've waited till she was completely gone before pursuing other interests. The new interest wasn't to happy with that. Maybe a trust factor. I can understand that, my fault.
My question - What can I say to the new girl to try and get the trust back or to get her to realize that the ex is completely gone??
Sorry for the long post!