I guess time and your gut will tell, but don't waste valuable time to find out. Don't postpone any tough talks to later. Spend a lot of time together in busines

I guess time and your gut will tell, but don't waste valuable time to find out. Don't postpone any tough talks to later. Spend a lot of time together in business maybe even private. Traveling with someone to a foreign country for me is always a good indicator. You'll see how someone behaves in a different cultural setting, how they deal with unknowns and eventually you feel if you can work hard together for the next 5+ years ;)