natalia, no KEMBONA is on the qualified list and very few 4GB sticks are there and they are much slower. I would guess KEMBONA ddr3 4gb will not work. Please go to the your MB page on the ASRock site and look at the Memory QVL list. I think the FX-4300 is compatible, please see the CPU Support List. I do not work for nor speak for AMD. This is mostly a user forum and I am a user. Good luck and enjoy, John.
If you are interested, here is the RAM MEMORY QVL List for your Motherboard from ASrock Support: https://www.asrock.com/mb/memory/N68C-GS%20FX.pdf
KEMBONA RAM MEMORY seems to be a Chinese made RAM Memory. Since it is listed on Chinese etail sites such as Alibaba and DHGate which deals with Chinese and Asian made products and nowhere else when I googled the RAM Memory.
If you already purchased the RAM Memory go ahead and try it and see if your computer boots up and works. But if you start having memory type issues or other strange issues than it probably isn't compatible. Best advice is to purchase a RAM MEMORY from the QVL List for best results.
The QVL List is a list that the Manufacturer of your Motherboard have tried and tested for compatibility issues with those particular RAM MEMORY Modules listed. If you RAM MEMORY is not listed is because it hasn't been tested to see if it is compatible or it was found to be not compatible with the motherboard.