White hat is a self applied label, so it tells you nothing on its own. What matters is whether the specific tactics in a proposal are the kind search engines say they act against, and that question has published answers rather than requiring a judgement call about anyone's character.
Read the proposal against the published guidance
Google publishes guidance on hiring an SEO and on link practices it considers manipulative, including links paid for in money or goods without appropriate qualification, and schemes whose purpose is ranking rather than readers. Ask any supplier to describe exactly how a link is obtained and what changes hands. The answer either fits that published description or it does not, which turns a marketing claim into a checkable fact.
What legitimate work actually looks like
Producing something genuinely worth referencing and then telling relevant people it exists: original research or data, a tool that solves a real problem, expert commentary that a journalist can quote, or documentation of something nobody else has written down. The work is mostly creating the asset, and the outreach is the smaller part. Proposals that are nearly all outreach with a thin asset are usually buying placements, whatever they are called.
Questions that reveal what is really being sold
Ask whether money or goods change hands for any placement, and if so how it is qualified. Ask to see the last ten links obtained for another client, and look at whether those pages have readers. Ask what happens if a placement is removed. Ask whether the same site appears across many clients. Vague answers to specific questions are the signal, because a supplier doing legitimate work finds these easy and unembarrassing to answer.
Judge it on the right measure, and keep the exit
Link counts are an activity measure, not an outcome. Agree what you are actually trying to move, visibility for defined terms or qualified enquiries, and review against that. Keep your analytics and search console in your own accounts so the claims are checkable. And treat guaranteed placements or guaranteed rankings as the warning they are, since nobody selling either controls the system they are promising about.
Questions people ask about white hat link building services
What makes link building white hat?
Not the label. Compare the specific tactics against the published guidance on manipulative link practices, including links paid for without appropriate qualification and schemes aimed at rankings rather than readers. Ask exactly how a link is obtained and what changes hands.
What does legitimate link building involve?
Creating something worth referencing, original research, a genuinely useful tool, quotable expertise, and then telling relevant people it exists. The asset is most of the work; a proposal that is nearly all outreach is usually buying placements.
How should we measure it?
Not by link count, which is activity. Agree the outcome you want, visibility for defined terms or qualified enquiries, keep analytics and search console in your own accounts so claims are checkable, and review against that.