A. 彼は大学生ですよ
B. 彼は大学生なんだよ
What difference that なんだ makes in this sentence?
For A, I understand it well as "He is a college student!"
For B, eventhough i have read much article written about なんだ... I still cannot understand it.
I notice that there are な+んだ or 何だ.
I feel that it was the な のだ, but i still wasn't sure as to how it changes the meaning of sentence.