I bought a J color diamond ring.it looks great outside but yellowish inside sometimes:( is this normal?

I compared it to H color diamonds before I bought it and it seemed brighter white. The jewelers told me it was because the J diamond was either graded wrong or just because the cut was so good. I dont know if its in my head because I know its a "J" color. I have heard that the inside light is just reflected back and that the bulb is a soft white and that is why it appears yellowish..Like i said, outside it looks amazingly white. Please help!