So you make your pitch to an investor and get a great response and interest. You feel elated and think that things are all set. Maybe, likely not. Look at this quote from a BBC producer:

"After the initial agreement is made on camera, both parties enter a period of due diligence. Sometimes during this period the deals fall through." Via Some information about the Dragon's den TV show

Due Diligence, it is a legal term that describes a period of time when an investor or buyer gets to "look under the hood" and poke around the business to satisfy themselves that representations made by the owner or seller are accurate.

Deals with investors can go Sideways at any point along the way for any number of reasons. Until you cash the cheque, it is not officially a deal.

Look over these statistics from the Dragon's Den and you will see what I mean. Some deals were made and many were not. Make sure you are realistic in your expectations and don't make plans for the cash until you actually get it.