You're starting off by trying to prove a negative. (You're trying to prove that by using this product something wont happen). Proving a negative is in many cas

You're starting off by trying to prove a negative. (You're trying to prove that by using this product something wont happen). Proving a negative is in many cases a fool's errand. In your particular case you're using a logical fallacy called "argumentum ad ignorantiam" (Asserting that something is true simply because it has not yet been proven false). Anyone with a math background, a technical background, a law background, or or a formal-logic background will automatically feel uncomfortable with the kind of claims you're making. Though they may not be able to articulate why they don't trust you, I'd wager that's the underlying cause. To gain trust, you'd need to restructure your offering, brand, and marketing efforts in a logically valid and sound way. Think about what you can prove logically; don't overstep or use hyperbole, and err on the side of conservative claims. Then people might warm up.