One thing I've learned from working with countless launch campaigns: affiliates don't need to believe in your product the way you do. They need to believe it converts, pays out reliably, and won't damage their reputation with their audience.
It's a bit like fishing with bait they can actually see. Before you ask for a big push, give them proof over potential - a clean landing page, a decent conversion rate, fair commission terms, low refund numbers, fast payouts, working tracking, and creative assets they can drop in without fuss. If you don't have that track record yet, start with a handful of smaller creators and treat it as validation. Offer them clean numbers, not just promises.
Also, keep the first ask small. Most affiliates won't gamble their list on an unproven offer, but they'll test a simple placement if the terms are transparent and the effort is minimal.