Jonah Wants to Propose to Rhonda and Goes to a Jewelry

Jonah wants to propose to Rhonda and goes to a jewelry store to purchase an engagement ring.After college,Jonah had worked as a jeweler while going to law school,and he is now an attorney.He still remains knowledgeable regarding the jewelry industry.In the jewelry store the owner listens to what Jonah wants,and he takes a diamond ring from a showcase.The jeweler tells Jonah that it's a class AAA perfect blue-white stone in a platinum setting and the price is $5,000.Jonah,without indicating his jewelry knowledge,asks to use the jeweler's loupe (eyepiece)and,upon inspection,sees that it's a class AA yellow-white diamond with three minor flaws.He furthermore realizes that the ring is worth only $4,000.The ring is beautiful,so he decides he'd like to buy it.He asks if the price is negotiable,and the jeweler offers a sale at $4,500.They settle on $4,300.When Jonah proposes,his girlfriend says no.Dejected,Jonah seeks to return the diamond ring but the jeweler refuses,so Jonah sues the jeweler for fraudulent misrepresentation.Who wins and why?