What did Elisha promise the Shunammite woman?

Answer: A son

Elisha promised she would hold a son in her arms about that time next year.

“And Elisha declared, “At this time next year, you will hold a son in your arms.” “No, my lord,” she said. “Do not lie to your maidservant, O man of God.” But the woman did conceive, and at that time the next year she gave birth to a son, just as Elisha had told her.”— 2 Kings 4:16-17 (BSB)