Here's why:
* Hesitate, vacillate, and dither all mean to be uncertain or slow to act, often due to indecision or doubt.
* Ameliorate means to make something better or improve a situation.
Let's look at some examples:
* Hesitate: "She hesitated before answering the question."
* Vacillate: "He vacillated between two job offers."
* Dither: "They dithered over which restaurant to choose."
* Ameliorate: "The new policy aims to ameliorate the current economic situation."