What is noun form of sell?

The Word 'sell' is both a verb and a noun.

The noun 'sell' is an informal noun for the activity of persuading someone to buy; the activity of causing to be accepted; a deception or hoax; a Word for a thing.

Example: The salesman tried to give me the hard sell.

The noun forms of the verb to sell are seller and the gerund, selling.

Examples:

I will contact the seller with your offer.

He has a winning personality, perfect forselling.