If she is fan of sports, find a game where her favorite team overcome a very big deficit.
Her: There is no sense in playing, it's over anyways.
You: Did the Patriots quit when were losing by 28 points? No, they keep playing and won the super bowl.
https://www.youtube.com/watch?v=016LXFHpFCk
Or something like this: https://www.youtube.com/watch?v=vAPmqbY6Omw
You can also share and discuss quotes like:
As an inventor, Edison made 1,000 unsuccessful attempts at inventing the light bulb. When a reporter asked, "How did it feel to fail 1,000 times?" Edison replied, "I didn’t fail 1,000 times. The light bulb was an invention with 1,000 steps."