Marketing is the larger part that includes other functions besides selling which is just one of them. The other functions include the product, pricing, promotion, distribution and so on all of which ultimately lead to the sale of the product.
When you visit a mall, you may have noticed the glitz and glamor of the shops displaying the best of their clothes, shoes, accessories etc. That is a part of marketing to attract the prospective buyers to purchase their product of interest.
As you enter the shop inside a mall, you may again notice a board hanging that says 'discount upto 50%' or 'buy 1- get 1 free!' This is also a part of the marketing strategy that lures you into buying the product that has such offer.
Selling is just a narrow term that just involves a transfer of goods and services from the buyer to the seller for a price and thus may create profits or losses for the company depending upon the volume of sales generated.
Business tycoons such as Donald Trump, Warren Buffet or Mukesh Ambani have made their mark in the respective industries through their successful marketing strategies and not merely by selling.
“Good companies will meet needs; great companies will create markets.”
- Philip Kotler