Related Clues:

• Sign or support
• Leave no doubt about
• Give one's word to
• Nail down
• Corroborate
• Get behind, on the trail
• Give a guarantee
• Make free from doubt
• Allay worry
• Make certain of
• Support, as a candidate
• Sign the back of a check
• Tell positively
• Sign the back of a cheque
• Approve or underwrite