You never actually sell anything, a customer always buys something.
You can’t (legally) make a customer buy what you want to sell.
But you can convince them that the thing you would like to sell, will solve a problem they have, at a value that makes sense, from people they trust.
You can’t make them buy it when you need to sell it (quarter sales target anybody?)
But you can incent them to buy it early than they really need to, by offering a discount, adding more value for no extra cost, promising some extra value in the future.
Telling somebody you will get fired if they don’t buy from you is not a good approach. Remember you will probably try and sell them something else in your next job.