Assuming that you actually get here to this part, here's some reasons that your banking email is fake, aside from the fact that emails like this are ALWAYS a scam.

If you have read about how to identify a scam email (which is here) then in addition to things like bad grammar, poor spelling, even poorer punctuation, the use of free email servers, etc. these are some other things that make a "banking" scam format completely bogus.

1. I am a banker in....
No, you did not receive an email from a banker. You did receive an email from a criminal. His objective is to steal your money. If you delete the email he can't do that.

2. I discovered some money and put it in a suspense account.
No he didn't. Banks DO use suspense accounts. These are temporary accounts (like 24 hours) that are internal accounts which banks use for accounting purposes within the bank. You cannot "discover" millions of dollars in a bank and you certainly can't find them in a suspense account. Banks have internal auditors and the first thing auditors do is check suspense accounts. In short, you cannot hide millions of dollars in a bank at all. Someone would know it. You got a scam mail from an idiot scammer and the best thing is to delete the email.

3. I have a business proposition for you..."
And whatever it is would be illegal if there was any actual money involved but the only money involved is yours. Just delete the email because the only deal you will get is a bad deal.

4. We have been mandated by the United Nations/ IMF/ World Bank....
No, they haven't. The United Nations does not mandate anyone to do anything. Neither does the IMF or the World Bank. The short answer is that no one gives you money for nothing, not a bank, not the United Nations etc. These are emails from criminals who want to steal your money. Just delete them and don't respond to them.

5. "I am a banker and I want to send money to you!"
Yeah. Just think about that one for a minute.

6. "I work for a bank and I want you to send money by Western Union".
What? They're in a bank. Why do they need you to use Western Union? Because this person does not work for a bank. Scammer/criminals don't like to work with bank-to-bank transfers because banks require ID and Western Union doesn't. Criminals do not use banks. Except to launder money and that's a different subject.

7. "I will prefer to contact each other via mail as i cannot acknowledge any phone call. "
That's because in the event that you did actually call the bank and ask to speak to this person you would find out that:
a) this person works for the bank but his or her identity has been stolen by internet criminals (and he or she would have no idea what you are talking about) or
b) this person is entirely fictitious and no such person works in the bank.
That's because you received a scam email from an internet criminal. You did not receive an email from a banker. To avoid your eventual disappointment as well as long distance charges, the best thing to do with the email is to just delete it.