[joelennon]

Tread carefully starting a business with someone you don't know. If you decide to forge ahead, you'll need to get to know the person not just professionally but personally. I've seen several co-founder relationships (including my own) break down due to personal circumstances that could probably have been predicted had there been a stronger personal relationship prior to starting out. Above all else, discuss at length "what-if" scenarios for every conceivable outcome, in particular the ones that you don't think will happen (like one of you deciding to leave). Get a founders agreement and get a lawyer to translate it into legalese. Put vesting in place so you don't run into tax issues clawing back shares if she decides to leave. Don't wait until you're further down the road, do it straight away.

As for determining if she is the right person professionally, I'd make a list of all of the things that...

1. You suck at

2. You hate doing

...that will be necessary to succeed. In a perfect world, she will excel at many/all of these things and love doing them - allowing you to divide the workload and each focus on your strengths. Don't take her word for it - find out, test her, check references, do whatever you have to do to be comfortable that she is the right person.