assure(v.)
使确信 
　　　
例句：
John assured¹ me that he was an excellent cook.
约翰要我确信他是个很高明的厨师。

the apple of one's eye
某人的掌上明珠
 
例句：
Mary, as the youngest daughter, is the apple of her parents' eye.
作为家中最小的孩子，玛丽是她父母的掌上明珠。

I con't catch your meaning
我不懂你的意思 
　　
对话：
A: I can't catch your meaning. There are so many terms that I don't know.
B: Sorry. I will explain them to you.
　　　　　　　　 　　　　　　　　 　　　　　　　　 　　　
A：我不懂你的意思，你用了太多的术语。
B：对不起，我会给你解释的。