Greetings.
I don't use GUI on Pi so I can't give you a direct solution to this.
I think the problem is that you need a Chinese font.
It's not Pi's problem. I'm using a Chinese version Windows 10 and PuTTY to access the Pi, I could read Chinese. It's Windows who is rendering those characters. I'm not sure if the Pi itself have a Chinese font either.
You could get an open source Chinese font from:
https://en.wikipedia.org/wiki/WenQuanYi
And for the Simplified Chinese, Microsoft made their own font, the Microsoft YaHei. It's really good. You could copy it from PC to Pi. However I see you are accessing a Hong Kong site, so maybe it's Traditional Chinese font you are looking for. Anyway, you could try copy some fonts from your PC.
Edit: I've searched the apt repo, there is a package named
task-chinese-t whose description is:
Traditional Chinese environment
This task installs programs, data files, fonts, and
documentation that make it easier for Chinese speakers
to use Debian, using the traditional Chinese encoding.
Maybe it worth a try, install it via:
sudo apt install task-chinese-t
Edit again: There is a thread about this:
http://crunchbang.org/forums/viewtopic.php?pid=435706
It looks like the solution is installing the Droid Sans font from the Android project:
sudo apt install fonts-droid