Take these two sentences.
1.I want him dead.
2.I want him to be dead.
What is the differences between two sentences? What does the "to be" mean?
In most contexts, the two sentences mean the same thing, since "to be" is implied in the first one. "I want him to be dead" means "I want that he be dead", or "I wish that he were dead". I cannot really explain the grammatical usage of "to be" in this context beyond saying that it is, in an way, idiomatic. I suppose it is kind of a linking verb connecting the direct object and its adjective, but emphasising more that he must be dead rather than that you want him.
To some extent they can even mean the same thing. However, there is a difference.
The first one is typically where (for example), you are ordering that someone be killed. This is like in paid contract to kill someone. So you want the killing done on your behalf.
In the second sentence, it's more like you're wishing that someone is dead.
"to be" means that the state of what you're expecting must be 'dead'. Perhaps for a question like this, it may be a good idea to state what your mother tongue is. This way someone with a knowledge of both your language and English may give you a better answer.
Both are correct.
The first sentence has "dead" has the object complement; the second sentence has "dead" as a sort of predicative adjective in the infinitival clause.