I am going to take a stab in the dark and assume you are white, and like Asia because you like foreign countries, asian ladies (there's no shame in that), and your gf.
I am being deliberately specific because it means you have two different things to consider.
1- LOGICAL Assessment
Without Cantonese, or a profession, I cant see any reason why a HK company would hire you.
But you do have what Singapore wants though.
Being a mandarin speaking white male makes you creme-del-a-creme in singapore, both in terms of jobs and socially.
Singapore speaks (semi) fluent English and (semi) fluent Mandarin. You speak both, so you have natural skills. SG is also easier to get into visa wise (depends on the job of course, but in general). English tv, radio and magazines are everywhere and there is almost no adapting for you to do, besides the tropical weather, esp compared to a year in China.
Many companies in SG do business in China. Again, you have actual hands on experience.
I dont think you mentioned your actual qualification, but I assume you dont have a profession per se. So use the skills you have.
2- EMOTIONAL assessment.
So your CV really says Singapore, but your heart says HK.
You mention your gf is "canto". Is she actually from HK or the nearby GuangDuong (sp?) province? If from China, then again you have natural skills allowing you to get a job- interpreter, teacher, in China.
If HK, then how close are you to the gf? Does she have a job or profession? Would you stay together in a LTR if you went to SG and she was in HK? As mentioned above, they are only 4 hours apart.
Good luck to you in finding a job in HK.
But I have to say I have yet to hear of a young Caucasian with no skills finding a job and staying in HK. Perhaps others on the forum do know of such ppl.