When constructing a persuasive/argumentative essay, what you'll basically be doing it presenting your point of view on a certain element within the play then defending it with three points. A good thesis sentence might include an opposing viewpoint and sound something like this:
Even though some might say that the love Romeo and Juliet had for each other was immature, (Reason #1), (Reason #2), and (Reason #3) prove otherwise.
Remember that the points/reasons within the thesis sentence will be the topics of the body paragraphs in the exact order they will appear within the paper.