"What the DPRK [North Korea] needs to do is to get serious with denuclearisation.
"If they get serious with denuclearisation, a lot of good things can happen ... if they do not get serious about denuclearisation such things will go away," said Hill.
Kim had voiced pessimism on Saturday over the talks and accused the US of pursuing a "hostile policy".
The six-nation talks have been plagued by delays and discord since they began in August 2003.
The US and Japan have sought to line up Pyongyang's regional neighbours, China, South Korea and Russia, to impose sanctions against a nuclear North Korea.
But the North has instead exploited differences to delay disarming and buy time to further develop its atomic arsenal.
North Korea's October 9 nuclear test of a device believed to be relatively small in explosive power has apparently hardened the will of other countries - particularly key benefactor China - to persuade the North to disarm.
A series of bilateral meetings between the six parties were held on Sunday before a welcoming banquet, Chinese officials said.
Hill said he would probably meet Kim in a bilateral meeting on Monday, with other diplomats saying the likely topic would be US sanctions that led to North Korea walking out of the talks last year.
"I'm neither pessimistic or optimistic," Hill said after a banquet in the Chinese capital during which all the delegation chiefs shook hands.
"We'll know tomorrow whether we are going to make some progress or not."