If you can’t hear yourself, you can’t hear anyone.
Are your strong words stopping you from listening? When you use phrases like “I’m certain of it” or “I know for a fact”, you are essentially saying you’re not open to listening. You’re not open to hearing another point of view.
Face it, you’re just being stubborn. Even if you think you do know something “for sure”, tone down your language if you expect to have a meaningful conversation.