Ask the kinds of questions I posed. Get involved in a discussion more than a question/answer session, though that is important too. A discussion will help you gage their passions and goals better.
If you ask if they would believe in the project, then of course they may say yes. If you ask what comes first, the project, a current paying job or family, then of course the latter two will be priority. You cannot expect someone to put the project first because as a business is built and matures, it moves up in rank over time.
Finding a partner is a whole lot like dating. After all, there you`re
looking for a "life partner," to use weird modern language. :-) But
there are two milestone points in any relationship like this.
The first is finding someone with the same interests, goals, desires,
dreams, hopes, aspirations, and (most importantly) sense of humor.
The second, usually comes after an initial commitment has formed.
That`s when the two of you suddenly plunge into a serious problem
situation. A partner stands with the business, regardless of the
difficulties, and doesn`t abandon ship.
If you can`t find someone like that, there`s no reason why you can`t
consider hiring employees later on. Build as much as you can yourself,
until you have some money, then go with the employee structure. Both
ideas have their benefits.