Answer:
by encouraging Romeo to think logically and consider his options
Hello. You did not inform the speech to which this question refers, which makes it impossible for it to be answered accurately. However, I will try to help you in the best possible way.
If King was trying to be persuasive, lines 307 - 334 can only affect persuasiveness by reinforcing the argument King is making. This can be done through a clear and objective diction that reinforces the importance of King's words. In addition, these lines can create a logical, ethical or emotional structure for the speeches, proposing a greater connection between king and the public.
It depends what you are writing,some can be factual/informal,others persuasive ect