1) North Korean's aren't stupid
Many people worry that N Korea is not smart enough to realize what trouble they would be in if they attacked the South--but they know. We normally like to portray our enemies as crazy idiots in order to make ourselves feel better. This allows us to feel less worried about them winning, and it also allows us to be less merciful when dealing with them. However, it would be wrong to say that Kim Jeong Eun is stupid. He might be young, but he has managed to rule as a dictator (or at least pretend to rule) for a year without getting killed. He also received his education in Swizerland, so he knows we aren't joking, and that N Korea would quickly lose (cease to exist), although it would be absolutely awful for both sides.2) China doesn't want war & they don't like N Korea
We may not be comfortable with China, and China might not be comfortable with us, but this time around, China does not want N Korea to get into a war for several reasons. First, China does not want a war on its border, with 10 refugees sure to flee to China. They already see N Korean's as a social problem (they way many Americans see Mexicans), so they do not want any more N Koreans in China. Second. China knows that N Korea would lose, resulting in a unified Korea. The unified Korea would naturally fall under the American sphere of influence, and would still contain numerous US bases, except, that now there is no N Korea to act as a buffer for the American threat.The Chinese also find North Korea an embarrassment. The Chinese people are even free to insult the N Korean government (this is a big deal because there is no freedom of speech in China). They call Kim Jeong Eun "The third fat Kim," because his dad and grandad were also fat while their people were starving.
3) We have anti missile technology
Our anti-missile missiles might only be 90% accurate, but we can shoot 2 and be 99% accurate.4) You can't even mail a nuke from N Korea
Mail doesn't really travel between N and S Korea. May be they could get Seoul with a cannon-nuke assuming they can make them that small.5) S Korea doesn't want war
If there were a war, South Korea would probably lose millions of people as causalities. This is because Seoul is less than 30 miles from the border, and has lots of cannons filled with bio and chemical weapons pointed at it. Luckily, we are not in Seoul.6) S Korea has a potentially angry big brother
Lets face it, if N Korea nuked anyone, we would have no problem wiping them out. Russia and China don't support them, so there would be no consequences if we did. The South Koreans call us their older brother, and they say that when older brother is angry it's like coming home to a house where the gas has been leaking for several hours.And that is why there won't be a war. The US and S Korean governments have both made a point that this is a paper tiger, and that no one should be worried. The only reason we are sending weapons is to appease the voters. We also want to keep the N Koreans thinking that their threats are taken seriously, so they don't try and prove that they are serious. That would be bad.
Hopefully you have stopped worrying.
-Riley and Margaret
This is a American made video that is essentially fake N Korean propaganda it may be funny depending on your sense of humor: Adventures of Kim Jeong Un