Warm visitors already trust you a little; cold visitors do not. The proof on a paid social page has to work for someone who has never heard your name. That rules out most of what pages usually offer: a row of anonymous five-star icons, a quote with no name, a claim with no context.
What works is specific and human. A short testimonial with a real first name, a photo, and a concrete before-and-after is worth more than a wall of logos the visitor does not recognise. A screenshot of a real result, a short video of a real customer, or a plain description of exactly what the product did for one person all read as true in a way that adjectives do not. Place the strongest piece directly next to the call to action, where the doubt is highest, and not in a carousel further down.
If you do not have many customers yet, say what you can truthfully say: how many people have used it, what the first users reported, what you do if it does not fit. Honest, modest proof beats inflated proof with a cold audience, because the cold audience is already expecting to be sold to.
If you are not sure whether your page's proof and first screen would survive a stranger's ten seconds, a landing page audit scores both and shows you what to fix first.