confirm

establish or strengthen as with new evidence or facts; "his story confirmed my doubts"; "The evidence supports the defendant"

strengthen or make more firm; "The witnesses confirmed the victim's account"

make more firm; "Confirm thy soul in self-control!"

support a person for a position; "The Senate confirmed the President's candidate for Secretary of Defense"

administer the rite of confirmation to; "the children were confirmed in their mother's faith"