This guide serves as a comprehensive resource for evaluating AI data security solutions, specifically tailored for CISOs, data leaders, and AI/ML leaders. It outlines a five-domain requirement framework essential for assessing the security of sensitive data in AI applications. The guide emphasizes the importance of defining security requirements before engaging with vendors, ensuring that evaluations are based on consistent standards rather than vendor pitches. Each domain includes must-have criteria, relevant RFP questions, and potential pitfalls to be aware of during vendor assessments. The framework covers critical aspects such as data discovery and classification, data-level protection, governance and access control, operational efficiency, and compliance evidence. By following the structured approach provided, organizations can effectively score vendors and make informed decisions regarding their AI data security needs.