How to quickly figure out if a potential co-founder is the right match? (I will not promote)

I'm aware, that everyone recommends choosing a co-founder you've worked with in the past (for at least a year or so). But that's not possible for everyone (like myself). 😅 I'm "co-founder dating" random people from different co-founder pools and some through friends or their friends. What tips do you have to figure out in a quick timeline who is best for you in the long run? I've discussed values, work routines, personalities and how they like to approach problems or tough situations, etc. but it's just discussion so people may act in a different way in a real situation. Waiting for long (months) isn't an option, but I'd be willing to try other ways to find out who would be the best match! I know this is one of the most important decisions.