你想去对我说 means you want to go to speak to me.
How to ask a question: What do you want to come to talk to me about? I don't know where to put the word
How to say a normal sentence (not a question): This is what I want to go to speak to you.
這就是 我想去对你说什么 correct?
How to ask a question: Is this what you want to come to speak to me?