Possible Clues:

• Disbelieving
• Line taken after slippery customer turning up, appearing suspicious
• Cautious due to suspicions
• In slang, wary or suspicious - reely!
• Having that doubtful feeling
• Cautious about set-up in meadow
• Wary, lascivious look at beauty's derriere
• Hardly accepting
• Unwilling to confide
• Knowing about set-up in pasture-land