Never mind my comment. "N'est-ce pas" usually works, whether at the beginning or at the end of a sentence.

99% used, is " n'est ce pas" (as Viviane mentioned) 1% formal use, est-ce qu c'est le cas? est-ce vrai? ...etc.

It means: "Est-ce bien vrai?"

Depends. Do you mean "isn't it" as in "Isn't it your birthday today?" or as in "It's your birthday today, isn't it?"