Conversion is usually treated as a page problem. It is a sequence problem. A buyer has to clear four separate judgments, in order, and skipping one does not speed things up - it stalls them silently.
1. Credibility
Are these people real and competent? Answered in seconds, mostly by signals you do not control directly: how the work is described, what the writing sounds like, whether the evidence is specific.
2. Fit
Is this for someone like me, with my constraints? The most commonly skipped layer. Generic positioning fails here, and the buyer leaves without ever disagreeing with you.
3. Value
Is the outcome worth the disruption? Not features. The delta between their current state and the state you can evidence.
4. Trust
Will this go badly for me personally if I champion it? Handled with risk reduction: process transparency, references, a small first step.
You cannot pay for a later layer with more of an earlier one. Ten more proof points will not fix an unanswered fit question.
Practical use: audit any high-intent page by labelling every element with the layer it serves. The gaps are usually obvious within ten minutes.