RAG is not reliable just because it retrieves documents. Users need to know which evidence supports an answer, which parts are uncertain, and when there was not enough evidence to answer.

This is the role of citations and grounding. A cited RAG system links claims to specific passages, pages, rows, timestamps, or source records. A grounded system checks whether those sources actually support the claims.

Grounding reduces unsupported answers, but it does not eliminate them. The model can cite the wrong source, overstate what a source says, miss contradictions, or quote a passage that is related but not sufficient. Citations point to evidence. Verification checks whether the evidence supports the claim.

This chapter shows how to produce structured citations, verify support, estimate confidence, make the system abstain when evidence is weak, and catch unsupported claims before users see them.