Vてほしい V-te hoshii : Desire to Have Somebody Do Something
Compare the following three:
(1) この報告書がほしい（です）。 Kono hookokusho ga hoshii (desu). I want this report. (2) この報告書を読みたい（です）。 Kono hookokusho o yomitai (desu). I want to read this report. (3) この報告書を読んでほしい（です）。 Kono hookokusho o yonde hoshii (desu). I want you to read this report.
Although in English the verb "want" alone can cope with these three different types of desire expressions, in Japanese (1) the Adjectival hoshii, (2) the Adjectival suffix V-tai and (3) the combination of the Verbal te-form and hoshii are employed for the three cases, respectively.
Case (3) is newly introduced here. This is the desire to have a person do something. To indicate the person whom you want to do something, the phrase-particle ni is employed; thus:
これは山田さんに書いてほしい。 Kore wa Yamada-san ni kaite hoshii. I want Mr Yamada to write this. 山田さんに大阪に行ってほしい。 Yamada-san ni Oosaka ni itte hoshii. I want Mr Yamada to go to Osaka. 山田さんに、鈴木さんに会ってほしい。 Yamada-san ni Suzuki-san ni atte hoshii. I want Mr Yamada to meet Mr Suzuki.
The phrase-particle ni is employed in this construction because V-te hoshii implies a vector with the person as its target.
And for the same cultural reasons as hoshii, V-tai and other Adjectivals that express emotions (such as ureshii, kanashii, etc), this V-te hoshii construction also tends to be used in the Nominalized Predicate. Thus:
これを今すぐコピーしてほしいんです。 Kore o ima sugu kopii-shite hoshii n desu. {It's that I want you to photocopy this immediately now} I'd like you to photocopy this right now. 　 　　 アルバイトの人にこの書類を鈴木さんに持って行ってほしいんだけど… Arubaito no hito ni kono shorui o Suzuki-san ni motte itte hoshii n da kedo... {It's that I want the part-timer to take these documents to Mr Suzuki, but...}　 I'd like the part-timer to take these documents to Mr Suzuki, but ... 　 　　 すみませんが急いでほしいんです。 Sumimasen ga isoide hoshii n desu. I'm sorry but I'd like you to hurry up, please. 　 　　 これぜひあなたに見てほしかったんです。 Kore zehi anata ni mite hoshikatta n desu. I wanted you to look at this by all means. 　 　　 実は彼には来てほしくないんですよ。 Jitsuwa kare niwa kite hoshiku nai n desu yo. To tell you the truth, I don't want him to come.