What would make you trust a cleaned CSV before importing it?

I’m building CSV Repair & Deduper and want to understand what proof matters before someone imports cleaned data into a CRM, store, or accounting system.

Which would give you the most confidence: a before/after row count, a list of duplicate groups, a change summary, column validation, or something else?

The tool runs locally in the browser, but local processing alone does not prove the output is correct. I’d rather prioritize the audit evidence people actually use. Please don’t share real customer data—just the checks that matter in your workflow.