It took 15 years for German to normalize the econocy after Germany unification.

It took 15 years for German to normalize the econocy after Germany unification.
Exchanging lettters and postal packages must be the first step before the unification of Korea.
I do not think it is not easy exchange letters without approval of North Korean officials.

Korea's unification will be beneficial to the whole Estern Asia

Korea's unification will be beneficial to the whole Eastern Asia.

East Asian countries are afraid of the nuclear weapons that North Korea has.
North Korea sometimes shooting missiles over the sea near Japan.

North Korean regimes is sending a message to the world.
"Do not touch me. We will live in our way."

North Korea is like a gangster in the Street of "East Asia".

Korea's unification would not be threat to China.

Korea's unification would not be threat to China, but Chinese government is afraid of the inflow of North Korean people after the unification of Korea.
Some North Korean officials committed crimes against North Korean refugees and defectors.
They tortured North Korean refugees after North Korean refugees were sent back to North Korea.
They must be responsible for their crimes.

Chinese government is also afraid of facing US forces face to face.