How, after 8 years of failure, do you maintain faith that you have the talent?
You keep working. Talent isn't something you're born with, it's something you develop over time.
Science has verified this - the level of talent you're "born with" only relates to how fast you can pick up a discipline. It has no bearing on the quality of your product once you get to the level every other non-amateur, professional artist is at.
That mythology about Mozart writing a symphony at 4 years old, or whatever? That didn't come from some kind of natural genius. He wasn't a savant, he wasn't on the spectrum. It came from his tiger dad forcing him to practice 14 hours a day from the moment he had sufficient hand-eye coordination to manipulate the keys of a piano.
Keep working. For years. Eventually you'll be talented. It's not a question, it's a guarantee.
Here's a quote by Ira Glass that encapsulates it perfectly:
Nobody tells this to people who are beginners, I wish someone told me. All of us who do creative work, we get into it because we have good taste. But there is this gap. For the first couple years you make stuff, it’s just not that good. It’s trying to be good, it has potential, but it’s not. But your taste, the thing that got you into the game, is still killer. And your taste is why your work disappoints you. A lot of people never get past this phase, they quit. Most people I know who do interesting, creative work went through years of this. We know our work doesn’t have this special thing that we want it to have. We all go through this. And if you are just starting out or you are still in this phase, you gotta know its normal and the most important thing you can do is do a lot of work. Put yourself on a deadline so that every week you will finish one story. It is only by going through a volume of work that you will close that gap, and your work will be as good as your ambitions. And I took longer to figure out how to do this than anyone I’ve ever met. It’s gonna take awhile. It’s normal to take awhile. You’ve just gotta fight your way through.