The exile, who worked among elites in Pyongyang, believes the North Korean leader’s dynasty is “the most unstable” and “is going to be the shortest”.
He decided to leave the hermit nation after the execution of Jang Song Thank, Kim’s uncle, and has only been in the free world for a year.
The defector, whose identity has been withheld for his safety, told CNN: “I can tell you for sure, the North Korean regime will collapse within 10 years.
“Kim Jong Un is mistaken that he can control his people and maintain his regime by executing his enemies.
“There’s fear among high officials that at any time, they can be targets.
“The general public will continue to lose their trust in him as a leader by witnessing him being willing to kill his own uncle.”
Jang was expelled form the ruling Workers’ Party of Korea in 2013 after being accused of a range of crimes – from obstruction North Korea’s economic affairs to anti-party acts.
The defector said: “Kim Jong-un revealed his true side.
“I can tell you for sure the North Koreans who are in the upper middle class don’t trust Kim Jong Un. I was thinking about leaving North Korea for a long time. “
He made a risky escape and did not tell anyone of his attempt to leave, as he feared he could be captured or killed.
He decided to leave his family behind as he was confident he would be reunited with them one day.
But the defector added the regime will not collapse as long as Kim is alive, meaning death for the dictator is the only option.
He said: “We can only expect the opening or reform of North Korea when Kim Jong Un is removed by an external power. North Korea will not collapse as long as Kim Jong Un lives.”
Yet according to a survey by the Institute for Peace and Unification Studies at Seoul National University, support for the regime remains high across North Korea.
In 2012, when Kim took control, defectors surveyed perceived support at more than 70 per cent.
In 2014, 146 defectors said perceived support of the dictator dropped to 58 per cent, which is still high.
Chang Yong Seok, senior researcher at the institute, said: “The issue is with the future. How much trust Kim Jong-un can gain from his elites after the purges.
“The elites could be feeling anxious. There is a possibility that their loyalty and support will weaken.”
North Korea was condemned globally for conducting its sixth nuclear test on September 3, said to be an advanced hydrogen bomb.
The rogue state has denounced efforts by the US to impose new UN-backed sanctions agains the country.