Dear Jenny Lynn:

Your last paragraph reads reasonable to me: “I am leaving the 31st”- is definite and assertive enough. I  would  put a period after that instead of proceeding with the “so do you need”- just to make sure you clearly communicate to him that you are leaving on the 31st regardless of his choice to stay April or not.

How are you feeling regarding the upcoming exchange this evening, if he will show up in the evening, that is?

anita