If you can have an effect on people to change their feelings, then you are more likely to change their beliefs. With that being said, I try to look at the whole person and how logic and feelings go hand in hand. Neither of them can be overemphasized because too much logic doesn't focus on the whole person and too much feelings doesn't look out for the well-being of the other person. To find a balance, I will speak kindly, in a tone that makes them feel a certain way while speaking with reason. This way, if reason is too harsh, it won't be received as bad with a certain tone of voice.
Really good Christian, I like how you said it is important to speak with reason. I said something like that by not just reading off a script but really getting into and passionate about your speech.