[Student’s sentence]

 

もしもし、さくらホテルなんですか。
Hello, is this Sakura Hotel?

 

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[My correction]

もしもし、さくらホテルなんですか。
→もしもし、さくらホテルですか。
Hello, is this Sakura Hotel?

 

Since 〜んです includes the meaning of asking for an explanation, you should not use 〜んです when you are just confirming a fact.
Saying 「さくらホテルなんですか」 implies, “Please explain to me if this is really Sakura Hotel!” It gives the impression that you are doubting the existence of the hotel.

 

Examples:

あのー、次(つぎ)は東京駅(とうきょうえき)ですか。
Excuse me, is the next station Tokyo Station?
(= simple fact-checking)

 

あれ、コーヒー、飲(の)まないんですか。
Oh, you don’t drink coffee?
(= I’m curious why you don’t drink coffee.)

 

In the JLPT course, each lesson includes homework. Submit your homework, and I’ll provide corrections. I’ll break down Japanese grammar, highlighting mistakes and explaining structures and nuances in a simple way. Feel free to ask as many questions as you need—I’m here to help you understand!