Hello! Allow me to help!
Your question: Why is it significant that Tony and Maria repeat the phrase “tonight, tonight” over and over in their song?
My answer: These two phrases are the biggest indication of what this song predicts, as well; Tony's romance with Maria, the sister of the Shark gang leader, Bernardo, and the fact that, due to hatred and conflict between the Jets and Sharks, as well as tribal/ethnic loyalties, Tony and Maria's romance will not see the light of day.
Why is my answer correct? Good question! Allow me to explain: The fact that West Side Story, as a movie/musical, is a combination of so many different events that take place, which, in turn, fuel the various emotions, and therefore the dancing, is also what gives this great movie/musical its strength and enduring fortitude, and makes it as relevant, even today, as it ever was. So many things that went on back then, and still go on, also give West Side Story its strength. Urban gang warfare, racial & ethnic tensions, romances that take place across racial, ethnic, religious and socioeconomic lines, the immigration experience, conflict with the law, substance and alcohol abuse, and tribal/ethnic loyalties that result in protection and honor, and yet often have deleterious results, as well. There are romances across various lines that succeed and flourish, even resulting in dating and intermarriage as well as the raising of families, and yet, some romances/marriages go up in smoke due to tensions, hostilities, and hidebound, insular tribal, ethnic and cultural loyalties.
Hope this helps! UwU
-Maxwell
