I wish you would wait for me for three years. After that I will surely...

I wish you would wait for me for three years. After that I will surely...

I wish you would is softer than I hope you can, and request is heavier.

Wait for someone, for must be there.

For three years, this for before time must be there too.

I promise I will ... After that. The feeling of a promise is heavier. after that I will surely ... The feeling is that I certainly will.

After then is the time three years later. after that is the event that you waited three years for me.

So exactly how you write it depends on what feeling you want to give the other person, and what you this... What is it.