affirm

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To declare positively; assert to be true.
• intransitive verb To declare support for or belief in.
• intransitive verb Law To rule (a court decision) to have been correct; confirm.
• intransitive verb To assert that one will give true testimony equivalent to that which would be given while under oath.

from The Century Dictionary.

• To state or assert positively; tell with confidence; aver; declare to be a fact; maintain as true: opposed to deny.
• To make firm; establish, confirm, or ratify: as, the appellate court affirmed the judgment.
• To declare or assert positively or solemnly.
• To declare solemnly before a court or magistrate, but without oath (a practice allowed where the affirmant has scruples against taking an oath); make a legal affirmation. See affirmation.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To declare or assert positively.
• intransitive verb (Law) To make a solemn declaration, before an authorized magistrate or tribunal, under the penalties of perjury; to testify by affirmation.
• transitive verb (Law) to assert or confirm, as a judgment, decree, or order, brought before an appellate court for review.
• transitive verb To assert positively; to tell with confidence; to aver; to maintain as true; -- opposed to deny.
• transitive verb (Law) To declare, as a fact, solemnly, under judicial sanction. See Affirmation, 4.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb To agree, verify or concur; to answer positively.
• verb To support or encourage

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb to declare or affirm solemnly and formally as true
• verb establish or strengthen as with new evidence or facts
• verb say yes to