In your comment you say 'I think we can't use "will" in the sentence. But I can't explain why'.
You might be thinking of a different context, as in adverbial clauses introduced by "if", "when", "until", and the like.
For example, we say "When you arrive in Paris, give us a call", not "When you will arrive ...".
"I hope" however creates a noun clause, and it can have "will" to express a future event.
Here's a passage from a song ("Desperadoes Under the Eaves") that illustrates this point.
- And if California slides into the ocean, ("if" adverbial clause - no "will")
- like the mystics and statistics say it will, (noun clause - "will")
- I predict this motel will be standing until I pay my bill ("will" in the noun clause after"predict", no "will" after "until I")