I believe he would repeal it after the election.
I believe if he promised tax cuts he would never deliver. For one thing he doesn't have the power to cut taxes, for another he would make the promise hoping to mitigate the election disaster and then after the election he would come up with some half a**ed excuse why he couldn't cut taxes.
Look back on all his "promises" and tell me how many he actually delivered on. Answer: 0.