Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You haven't learned this reading yet, so here's a mnemonic to help you:
If you're the type of person who starts to stray easily, you'll end up saying sorry (それ) a lot. Even if you don't do it often, if you stray, say sorry!
The conversation quickly digressed.