Is there any other way to figure out something like this?
If you don't have access to any potential customers in your network, then you probably should kill the idea or partner with someone who does (but that's kind of difficult if you don't know any such person).
Yes, do this. Find 10 actual real-world users, and talk to each of them for 30 minutes. If you need some good tips on finding users, convincing them to talk to you, etc., see Steve Blank's "Four Steps to the Epiphany". At the very worst, this will still be less stressful than sales or political canvassing, because you're only asking people for their opinions (which they love to share) and not their money (which they prefer to keep). You'll probably need a list of at least 100 users before you find 10 who will talk to you.
I _guarantee_ this will open your eyes, and save you months of wasted effort. Been there, done that.
This idea was kind of a shot in the dark to start with - so I knew this was a possibility.
I am a big fan of Steve Blank's book. However, often in the past I would analyze, research, analyze and then ... nothing. I figured this time I would just get something up there - and then figure out what I'm building along the way.
I've found that customers are really crappy at telling you what they want, and product suggestions (and feature requests) should be treated with extreme skepticism.
However: they are absolutely brilliant at telling you what their problems are. Behind every feature request/product suggestion is a pain point of some kind; if you can find it, you usually can come up with a solution that is much better than what they would ever propose.
So: find a group of people who have a common problem. Once you do that, you're on your way.