Related Clues:

• 'Yeah, right'
• Positive
• 'You betcha!'
• Irrefutable
• Proven
• 'No problem!'
• 'Of course!'
• 'Let's do it!'
• Say positively
• Never-failing
• 'No sweat'
• Give one's word
• Warrant
• 'Oh, what the hell'
• Convinced