Why don't you do the experiment? I'm sure you would do it really well.
你干吗不做这个实验呢?我相信你一定会干的很棒的。
My dear friend, Mathilde. Let me tell you something. That necklace you borrowed from me wasn't a real diamond necklace. It wasn't valuable at all. The stones in the necklace were made of glass. It was worth five hundred francs at the most.