Google Privacy Policy — Keeping your information secure
Verbatim
“We restrict access to personal information to Google employees, contractors, and agents who need that information in order to process it. Anyone with this access is subject to strict contractual confidentiality obligations and may be disciplined or terminated if they fail to meet these obligations.”Read on the source page
Why this isn't verifiable
The promise is that Google grades its own employees against an internal need-to-know standard, enforced by an internal disciplinary process, audited by Google. Every word of the clause is internally administered. The data subject — the user whose data is on the receiving end — is not a party to the grading, the enforcement, or the audit. They read the clause and trust it.