"I know just what he wants".
As I already pointed out in another of your posts' reply:
You should get used to capitalize I (1st person singular pronoun) every time you use it, as well as any word starting a sentence.
Please note that you must not leave a space between words and question (or exclamation) marks. Besides, it is a good idea to include the sentences in question between inverted commas (or any other way that clearly marks their beginning or end) to make them clearer for the reader.
Student or Learner