Bitcoin halving makes it difficult to mine Bitcoins. That means it would come to the point that the number of Bitcoins in circulation isn't even increasing that much because of the high difficulty of mining. The total BTC in circulation would almost remain the same as day passes by and as more and more people invest in that remaining amount of BTC in circulation, the price would be higher.
I don't think this is quite right, the halving is about the number of coins issued. Halving the inflation of supply is so that total number will never exceed 21million of them.
Mining difficulty is to try and keep the the rate of issuance stable. Ie if someone with better technology starts getting more then difficulty increases to compensate, if people with all the fancy hardware stopped mining then difficulty would decrease.