>>33570021 (OP)
You don't. You developed crush on their public persona, one that is meant to be engaging and approachable. While it's quite possible quite some of it is how they are genuinely, it's still not how they're 100% when being themselves.
You don't know her, you're strangers, I suspect you're quite young and your feelings are just infatuation half-built on your assumptions, the way naive and easily exploitable people like to assume someone attractive is also a good person.
You would need to be a regular part of her life, one she'd be grateful for and not in a way of her being grateful for simping whaling. And that assuming she already isn't into/with someone - many/most attractive female streamers are, they just keep it private - both for privacy sake and so viewers like you can immerse themselves in the parasocial aspect.