It's not like Mrs Mooney cuts to the chase, though. At first, "she watched the pair and kept her own counsel" (that means she didn't say anything to anyone). This strategy had exactly the effect she intended because it started to get to Polly and Mr Doran. They knew she knew about them, and they knew she would pounce, they just didn't know when. It's got all the suspense of a horror flick, but it's supposed to be a love story.