Relinquish the emotion which rests upon a mistaken belief, and seek to feel fully that emotion which fits the facts. If the iron approaches your face, and you believe it is hot, and it is cool, the Way opposes your fear. If the iron approaches your face, and you believe it is cool, and it is hot, the Way opposes your calm. Evaluate your beliefs first and then arrive at your emotions.
Contrary to the popular idea, rationality doesn't mean denying emotion. When emotion is appropriate to the reality of the situation, it should be embraced; only when emotion isn't appropriate should it be suppressed.