Don't know what to do

I deal with real estate properties. Lately there was this man wanting to sell his property. I asked him to invest and he proposes a deal that if I agree with his proposal that if I will accept his love then he will buy that property and I will be the one to manage. I am offering him a beach front lot and he said he is willing to invest an 18M worth. I am thinking abt this. I don't usually believe but it seems he is serious. He is divorced but now happens to have a live in partner with a son. Am a single mom for many yrs now and my kids are grown ups but what he knows is that i still have a husband.. He said that we will keep it secret if ever. Is it possible for a man like him to be serious? I don't wanna jump on this right away it might end up to nothing. And what if he do not have a word? What shall I do to let him buy the property witout asking anything in return ? What can you say?

You're either a professional or you're not. Your ethics should be keeping you on the straight and narrow in this case...and there's no better sense than common sense.

This is going to open your self up to many problems, ethical, moral, legal. If it seems too good to be true it usually is.