Borrowing money from private investors

[Ryan Martin]

Good evening all, 

I was wondering what it is that you do when you would like to gain investors confidence in a deal? My biggest downfall right now is wondering what you guys use to get an investor under contract? Do you have a written document from a lawyer stating the conditions and terms of what you're borrowing and how long you have to pay an investor back? I want to make investors feel confident and want to be as trusting as possible. 

I have someone who wants to invest with me but I don't want to just say "Give me the money and trust me when I say I'll give you back more" that's very unprofessional. 

How do I go about doing this the right way?

Thank you as always. Ryan Martin.