You are out on a date, and get into a “heated” discussion on an interest or belief one of you may have. Instead of making this into a debate, or clearly showing how you may not agree in this situation, why not try to turn it into a Discussion. Ask questions, show some interest, even if you don’t agree, but the other person may feel strongly about it.
None of us will have the same opinion about everything, but it shouldn’t be the time to get into how you don’t. Try to turn the situation around, or change the subject. If this is something that you can’t see yourself being part of, or “living with” then you know this person is not for you.
But try to make the best of the situation, and you know it will just mean you won’t hear from each other again.