They won't intend to hurt you, but that won't stop the pain. Don't let them say no to you as a person by placing more value on the letter than it has. Let them say yes or no only to your script. Even the most insecure writer can achieve that. While Hugh Grant has made a fortune from charming diffidence, few writers do.
Writers have to be bold without being cocky.
Instead of thinking, know. Better yet, avoid referring to your opinions on the matter at all. Bravado and boasting is also a transparent sign of insecurity, so avoid that extreme. What you're aiming for is the happy medium. Be the James Bond of queries.