Intransitive verb and Godan verb
しぬ
死ぬかと思いました。
I thought I would die.
わたしのそ母は、がんで死にました。
My grandmother died from cancer.
私は絶対に死なないと約束するよ。
I promise you that I will never die.
This word consists of kanji with hiragana attached. Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means death, so the verb version is to die.
The reading is the same as the one you learned with the kanji.