I stayed with him all the evening, and it was on that occasion, to explain the emotion which he had shown, that

he confided to my keeping that narrative which I read to you when first I came.

1)  It was on that occasion...that he confided to my keeping that narrative...是强调句吗？

2）看不懂为什么这里是to explain the emotion...不定式是occasion强调成分的后置定语吗？

3）看不懂结构confided to my keeping that narrative： 这是什么意思? confided sth to sb， 如何理解这里的句子呢？

     另外后面的my keeping that narrative是动名词复合结构吗？

麻烦老师详解一下，非常感谢！