I read George Eliot in college religiously, and she was a major inspiration to me as a budding writer. So the first time I saw the quote it felt off to me -- a bit too peppy, more like something from a Hallmark greeting card.
Where's the proof that Degas ever said it or wrote it? You can't rely on Goodreads as a source because fake quotes and misquotations run riot there. And if you do a Google search you'll just end up finding one site after another repeating the quotation without any source at all.