North Korea has never named her, confirmed her age or acknowledged her as Kim Jong-un’s heir. Yet South Korea’s spy agency says the evidence is now unmistakable: his daughter Kim Ju-ae has “effectively” become the successor-in-waiting. The assessment, delivered in a closed-door briefing to the National Assembly’s intelligence committee, was shared with journalists by Youn Kun-young of the ruling Democratic Party of Korea on Monday. “The NIS sees Kim Ju-ae as having effectively entered the stage...