To make (a person) certain or sure (of a matter); to assure, inform certainly; to give (a person) legal or formal attestation (of).

transitive. To make (a person) sure or certain (of a fact, or that it is).

transitive. To make (a person) sure; to assure. Also in phrases used parenthetically to emphasize the truth of a statement, as I sure you.

transitive. To make (a person) certain, sure, or confident; to certify, assure; passing in looser… Const. with of. Obsolete.

transitive. To verify or affirm the authenticity of (a document, handwriting, etc.). Obsolete.

transitive. To free from doubt; to satisfy, convince of or against a particular contingency, that something might happen. Obsolete.

To secure, make sure or certain of; to make fast, fix firmly.

intransitive. With for. To give personal assurance of the truth or accuracy of (a statement or fact). Also with accuracy, truth, etc., as object.