I know the phrase "Accidents will happen". It is used all the time. It is used for many situations. It means that things do not always go as planned. In other words: some one makes a mistake.
"In the best-regulated families"...... じゃああ、たぶん
no matter how well you plan something,
no matter how well your family prepares for mistakes,
there can be failure.
I think it means that we are all vulnerable to failure no matter how well you plan.
a "family" can mean any kind of group of people (job, or school or country)!
むずかしだからわからなかったらわたしとつたえてください。
Accidents will happen in the best-regulated families. What does it mean for you?
Does anyone else know an answer for this question?