I am sorry to encroach into your privacy in this manner. This is a personal email directed to you for your consideration alone, I request that it remain and be treated as such only. I am a banker with HSBC here in United Kingdom
I have an interesting business proposal for you that will be of immense benefit to both of us. Although this may be hard for you to believe, we stand to gain £9.2 million GBP between us in a matter of days. Please grant me the benefit of doubt and hear me out. I need you to signify your interest by replying to this email.
Most importantly, I will need you to promise to keep whatever you learn from me between us even if you decide not to go along with me. I will make more details available to you on receipt of a positive response from you.