Sometimes, we don't sell what we've got, we sell what could be.
Book publishers, for example, buy non-fiction book proposals ($10 million for Bruce Springsteen's autobiography) not the finished book. The finished book almost never matches what they were hoping for, but the hoping is fun.
Venture capitalists, at least in the early stages of a company, buy hope as well. The numbers that might be, that could be, not the numbers you have now.
Understanding this, it's possible to draw a curve of hope and reality, over time. You need to be on a course toward the reality you seek, but bringing on partners is most effective when hope is ascending, not after reality sets in.