Possible Clues:

• Scoundrel, with promises of redemption � that's unusual
• Unusual; eager to learn
• Scoundrels hide debt? Strange!
• Strange - inquisitive
• Strange; eager to learn
• Eager to learn something strange and erotic
• Eager to learn, strange
• A villain promises to pay - and with a great deal of interest!
• Reprobate given credit notes with a lot of interest
• A scoundrel promises to pay? That's unusual!