I am afraid she will be angry with me for I have already promised her that I will help her that day. I don`t want to leave her an impression that I am always changing my ideas.

Why do you go back on your word? Doesn't what you promised still count?

Parents do promise to buy something and then renege, impose unrealistic expectations, or blame the kids for something they didn't do.

Don't be inconsistent. That completely confuses me and makes me lose faith in you.

He claims the president reneged on an agreement to give him the job after that vote.