to sweeten the deal 提供优惠
To add inducements to a proposed business transaction in order to make it more appealing. (NOTE: also "to sweeten up the deal")
Although the initial price I offered to my potential buyer was already low, I dropped it by ten percent to sweeten the deal.
虽说向有意的买方提供的报价已经很低,我还是提供了10%的优惠。