Which of the app is the best selling app and what is the sentiments polarity of it?
best selling app = MAX(MULTIPLY(Price, Installs));
SELECT T1.App, T2.Sentiment_Polarity FROM playstore AS T1 INNER JOIN user_reviews AS T2 ON T1.App = T2.App ORDER BY T1.Price * CAST(REPLACE(REPLACE(Installs, ',', ''), '+', '') AS INTEGER) DESC LIMIT 1