YOU SAID:
You never really know what he's gonna do next
INTO JAPANESE
あなたは本当に彼が次に何をするつもりなのかわからない
BACK INTO ENGLISH
You really do not know what he intends to do next
INTO JAPANESE
あなたは本当に彼が次に何をしようとしているのかわからない
BACK INTO ENGLISH
You really do not know what he is trying to do next
INTO JAPANESE
あなたは本当に彼が次に何をやろうとしているのかわからない
BACK INTO ENGLISH
You really do not know what he is trying to do next
You've done this before, haven't you.