Possible Clues:

• Emphatic confirmation
• 'You couldn't have!' retort
• Rebuttal to "You never ..."
• "You couldn't have!" retort
• Rebuttal to 'You never . . .'
• Strong confirmation
• 'Don't you doubt me!'
• Reply to "No, you couldn't have!"
• Pie piece?
• Emphatic confirmation of action