How to Make this deal work

[Harrison Ojimma]

Good morning everyone

I need help saving a deal 

I have a homeowner that wants to sell their property. They owe $30,000 on the property mortgage, but the property is worth around $20,000. We discussed doing the deal via Subject To deal, where I would take over the title and deed of the property and the mortgage stays in her name. She asked what kind of guarantees can I provide her that I would make the mortgage payments and not default leading to foreclosure? I told her that she would see that the mortgage but that wasn't good enough....what can I do to save this deal or how can I structure it on the contract to make her not fear that I won't pay the mortgage?

What's the best way to do a subject to deal to get over this hump??