"You want hot water."
Translation:तुम्हें गरम पानी चाहिए।
In Hindi 'want' happens 'to you', or at least that's the way I've come to think of it. Careful though because this is only true when using the चाहिए form (which can also mean 'should' when used with verbs, like तुम्हें जाना चाहिए = you should go). The other is चाहना, and there you don't need तुम्हें. For example तुम गरम पानी चाहते हो (same meaning as तुम्हें गरम पानी चाहिए).