Speaking just as a normal user with no expertise in data privacy etc, the things which negatively affect my trust in a service are:

- lack of a visible monetisation plan. If I can't see how you'll make money I will assume that'll it be through selling all my data to advertisers.

- A copy/paste Privacy Policy

- Being based in the US (prejudiced maybe, but not without reason). As a European I don't want my data on US servers and subject to ever seemingly weakening data protection laws.

- Not knowing who is behind the company. If I can't see Linkedin profiles, blogs or similar for the founders I will assume it's shady and walk away.

- Responding to questions about privacy with vague meaningless canned statements that don't address the issue.

- Inability to see exactly what the company stores about me. E.g. I can't see what metrics Google has generated from my GMail account to use for targeted advertising