Sometimes your gut just knows.
It's clarity sometimes sings above the echos of reality offered by our eyes which has been transfused within our brain.
At times we need to communicate what we sense.
The key here is to speak with tentativeness. Well it's always important to speak with tentativeness even when you are surely sure.
The only time when you can be sure/conclusive/convinced is when you are talking from the 'I'.
Leverage your brain for thinking and your heart and guts for feeling things out.