I doubt its actually going to solve stuff dude.
Why would Kim Jong-Un continue to fight the sanctions when he's already promised to relax his nuclear testing? If he goes back on his word, the sanctions go back on and he's wasted his own time. Why do you think he's lying?
It's all about doing nasty stuff in the background.
The UN isn't some kind of shadowy organization that meets in underground tunnels. It's a hugely public organization that holds tons of public debate among SC member states before these kinds of sanctions go into effect. The UN also publishes documents online. For instance,
here is the resolution that set new sanctions on North Korea in March.
The UN is still a load of ass for everything else it does.
For example?
They can say "yeah we'll improve" but that doesn't mean we should all rush to sucking off the UN.
Who is 'they'? Are you talking about the UN or North Korea?
UN has been and always will be a failure because the bigger powers (Particularly the US) use it to their own narrow interests.
Did you miss the part where China, North Korea's strongest ally, decided to support those sanctions as well? China has veto power in the Security Council too, so they could have shut it down if they felt that the UNSC was only catering to US interests.