You don’t need self-confidence. I mean, sure, it helps. But it’s not a condition for success in most cases. It certainly isn’t a condition for making an attempt.
All you need in order to make an attempt is the understanding of the risk it carries for failure. And in the vast, vast majority of cases, the risk is absolutely zero.
Ask that person on a date. If you succeed, you get the date. If you fail, you get shot in the stomach… wait? The person won’t shoot you in the stomach? There’s no risk at all?
Apply to that job. If you succeed, you get the job. If you fail, you’re out the $150 application fee… wait? It’s free to apply to that job? There’s no downside?
Most of life is like this. The “risk” of most things is just that they won’t succeed, but that’s the same thing that happens 100% of the time if you don’t try at all. Most things that you’ll want to do don’t require you to risk anything other than a small amount of time.