Michelle, if by telling her you risk losing out on the business deal of a lifetime, I would suggest holding off until after the deal has gone through. It is only another month, which is a small amount of time in the grand scheme of things.
I also think you should get to know her better before you do tell her. If you've no idea whether she is trustworthy or not, then your relationship has not progressed to the "need to tell" level yet. You are still strangers.
I would not walk away from the relationship out of fear of what she will do.
So .... instead of having her come up to your place in August, can you arrange to meet her somewhere else for an extended weekend?
