Question about smart contracts.

[DrBitcoin]

Let’s say two people want to bet on a game. They agree about the scores, they agree about the bet amount and they lock up money.

The problem is, what becomes the trusted data source?

Is there a way to also agree upon the data source?
We both agree that google is the truth. If google says the winning score is 10..:the truth is 10.
Is it possible for two parties to agree on the source of this data?