So I feel comfortable replying?
Faith is very complicated, IMO, because it is isolated, as far as spiritual concepts go.
I'll try to explain what I mean and then relate it to the verse, even though, I know nothing about it ( the verse )
A person can approach the divine from reason... the world is orderly and beautiful, there appears to me what looks like divine intervention making this happen.
And then that reason, can encourage a more emotional connection. This can be imagined as another step towards the divine. It could be described as longing, or a craving to connect with the "thing" the "one" the "architect" who made something so beautiful.
And then this emotional connection might encourage gratitude. And that is another step.
This gratitude might encourage mercy and virtuous deeds, why? Because if I am actually thankful, and I appreciate what I have, it's natural to want to share and to comfort those who don't have and those who are suffering... and then that's another step towards the divine.
And this chain of logic can continue for at least one or two more steps, but then it stops.
That's where faith takes over. It's beyond reason, beyond emotion, beyond gratitude, beyond mercy, beyond virtuous deeds.
Faith is lonley, isolated, and very very hard. But it's rewarding. That's my opinion.
You asked: "How does a person prove to himself whether or not he has faith based on this verse?"
I don't know anything about the verse. But I see the words, "substance", and I see the words "not seen". To me that means that faith is real, tangible and potent. Not seen means it's isolated, and all alone. How does one prove whether or not he has faith? They can't. It's not seen. But that doesn't mean it doesn't exist. It's just not seen, but still substantive. Does that help?
Maybe the verse is telling you, you don't have to prove it? And that agrees with my interpretation of faith above, because... faith is beyond reason. So why prove it? Why even try? Proof doesn't change its substance?