My mindset is quite different from the people of where I'm from, so this is what I'm going to do inshaAllah- ask conventional questions with unconventional answers. For example, ask 'what is the most important thing in your life?'. He'd most likely say 'my family, or mother, or job, or wife, etc." and think 'oh yeah, i totally owned that question'. Whatever it is he thinks you want to hear. When what you (I) really want to hear is 'islam, or 'pleasing Allah', 'following in the footsteps of the prophet muhammad peace be upon him'" etc. (of course, the answer we should get is the second one ideally, but we are far from perfection)
I guess this sort of thing has limitations, though, because sometimes the answer you want is conventional. But yeah, that's one thing I'd try doing.
Try to read their body language. Ask about them, observe their actions, to see if they agree with their words, or whether they talk the talk but don't walk the walk. Like thinker said, take everything with a pinch of salt. And ultimately, trust in Allah, that whatever is meant to happen will happen.