In the end, I couldn’t bear reading the work.
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 endure, so the verb version is to endure or to bear.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You learned this reading when you learned the kanji!