If, after concluding a deal, you try to pay with a credit card, he may then boost the price in order to cover the card charges.
If you pay with a credit card, he will give you a discount.
mnli hypothesis: If you pay with a credit card, he will give you a discount. premise: If, after concluding a deal, you try to pay with a credit card, he may then boost the price in order to cover the card charges.