con·firm 
(kən-fûrm)
(kən-fûrm)tr.v. con·firmed, con·firm·ing, con·firms
1.
a. To support or establish the certainty or validity of; verify: confirm a rumor.
b. To reaffirm the establishment of (a reservation or advance arrangement).
2. To make firmer; strengthen: Working on the campaign confirmed her intention to go into politics.
3. To make valid or binding by a formal or legal act; ratify.
4. To administer the religious rite of confirmation to.
[Middle English confirmen, from Old French confermer, from Latin cōnfirmāre : com-, intensive pref.; see COM- + firmāre, to strengthen (from firmus, strong; see dher- in the Appendix of Indo-European roots).]
con·firm′a·bili·ty n.
con·firma·ble adj.
con·firma·to′ry (-fûrmə-tôr′ē) adj.
con·firmer n.
Synonyms: confirm, corroborate, substantiate, authenticate, validate, verify
These verbs mean to establish or support the truth, accuracy, or genuineness of something. Confirm implies the establishment of certainty or conviction: The information confirmed our worst suspicions.
To corroborate something is to strengthen or uphold the evidence that supports it: The witness is expected to corroborate the plaintiff's testimony.
To substantiate is to establish by presenting solid or reliable evidence: "What I shall say can be substantiated by the sworn testimony of witnesses" (Mark Twain).
To authenticate something is to establish its genuineness, as by expert testimony or documentary proof: Never purchase an antique before it has been authenticated.
Validate refers to establishing the validity of something, such as a theory, claim, or judgment: The divorce validated my parents' original objection to the marriage.
Verify implies proving by comparison with an original or with established fact: The bank refused to cash the check until the signature was verified.
These verbs mean to establish or support the truth, accuracy, or genuineness of something. Confirm implies the establishment of certainty or conviction: The information confirmed our worst suspicions.
To corroborate something is to strengthen or uphold the evidence that supports it: The witness is expected to corroborate the plaintiff's testimony.
To substantiate is to establish by presenting solid or reliable evidence: "What I shall say can be substantiated by the sworn testimony of witnesses" (Mark Twain).
To authenticate something is to establish its genuineness, as by expert testimony or documentary proof: Never purchase an antique before it has been authenticated.
Validate refers to establishing the validity of something, such as a theory, claim, or judgment: The divorce validated my parents' original objection to the marriage.
Verify implies proving by comparison with an original or with established fact: The bank refused to cash the check until the signature was verified.