The best speeches always have a good mix of feelings and facts. If the speaker doesn't feel passionate about the topic, it will be much harder for the audience to connect. People tend to be drawn in by feeling and emotion. On the other hand, a speech must also be backed up by fact and logic. You have crossed a line when your whole speech is simply emotional rambling with no absolute truth. In order for the audience to truly be engaged, there has to be a good balance of authenticity and emotion, as well as trustworthy information. You can use Ethos as a way for your opinion to carry more weight, and citing/referencing sources you used is a way to do this.
Wow! You wrote this well, I have to agree with this, a good balance in everything is always better. I think that having emotions take over is crossing the line as well. As someone who is very emotional I have crossed this line before. Emotions are not facts.
I agree with this completely, it's good to have emotion but too much can just make it not credible, it's always good to have a good mix of the two.
I love that you used the word authenticity! I always enjoy other peoples speeches so much more when I can tell that the person is authentic and passionate about whatever they're speaking on.