What's the singular form of prospectiveness? Here's the word you're looking for.
Answer
The noun prospectiveness is uncountable.
The singular form of prospectiveness is also prospectiveness.
Examples
This is the second highest value gold intercept drilled at the Penasquito property and highlights the prospectiveness of the entire Outcrop breccia area.
My view of what is correct to say at this stage is that the prospectiveness is high.