Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
This situation has to end. You're the ower (おわ) of a lot of money. For this to end, you need to pay back all that money. Try to think of ways to stop being an ower so this stressful situation can end!
When school's finished, I'll go shopping.
My life was over when I lost it all gambling.
Hey, man! Back off! I told you to stay away from me until the atomic bomb has finished being dismantled.