Possible Clues:

• 'May ___ of service?'
• 'May ___ excused?'
• "How Can --- Sure"
• 'How can ___ sure?'
• "How can ___ sure?"
• Chicago "What Kind of Man Would ___?"
• 'How Can ___ Sure' (1967 hit)
• 'May ___ frank?'
• 'Can ___ dreaming?'
• 'Where would ___ without you?'