once they have password they can change your email
so all you need to give is your password, no need to give them access to your email account
If I were loaning you for this specific collateral I would ask for your password, that's it. It woudl then be up to the escrow/lender to change the details (including the email address) for the duration of the loan.
I would recommend having the account placed in escrow unless you trust the lender with your account.
If its possible to just handover the bitcointalk forum account userid and password and the lender can change the mail id only. Then i can lend easily.