certain to be achieved or won. means that something is certain to happen, guaranteed, or secured. The successful outcome is already assured.

With her experience, the promotion can be in the bag.

After the final negotiations, the contract is in the bag; we just need the signatures.

With a 30-point lead in the fourth quarter, the championship game is pretty much in the bag.

I nailed the final interview and the hiring manager seemed thrilled. I think the job is in the bag.

She finished all her coursework with A's, so the scholarship is definitely in the bag.