Olivier: "I hope your answer" is definitely bad English. "Hope" as a verb usually takes the preposition "for" when it's followed by a noun. (The farmers are hoping FOR rain. Jack is hoping FOR a pay increase. etc).
I hope FOR you answer is thus better -- although still not optimal in my opinion. I might suggest here a better fit might be "I await your answer." or "I'm waiting for your answer" or "I'm looking forward to getting your answer" or, simply, "I want your answer" or even "I need your answer."
The reason is: when we use hope + for + something, it's usually implied that the "something" is desirable or sought-after. But an "answer" could bring bad news, as well as good -- in other words, you might not get the answer you want! So, if you're going to use "hope for" + "answer" you logically would (likely) say something like "I'm hoping for an affirmative answer" or "I'm hoping for the answer I've always wanted." (or something similar; in another words, "answer" in such a case would probably be modified to explain WHY it's hoped for).
I hope that makes sense...