People only want to be ‘your friend’ at random because they want something. You don’t set out with the intention of befriending a complete stranger, unless maybe you have some philosophical imperative (I will make up for being such a git by being nice to the first person I meet.) today - but then the odds against your chosen new friend being a foreigner are astronomical.
So you’re being singled out because you’re a foreigner, because they want something. I imagine it’s either a free English partner or else they’re a-questing for some sex. Either way, it’s not real friendship. You make friends because you have good reason to talk to someone on a regular basis and decide that you like them, not because you like the look of them and decide to hunt them down.
So it’s not acceptable in my book. It’s fucking rude, and you’re under no obligation to put up with it.
First, ducking and weaving and walking away is no good. Try it when being pursued by a beggar in a less developed country and see how far you get. You’re giving them a psychological advantage by letting them chase you. Do not show any fear at all. You are a brusque, confident woman who doesn’t have time for this shit.
Wear sunglasses, the reflective kind. If they can’t make eye contact it disturbs them and gives you something to hide behind.
And get used to it. You’re in much less physical danger than you would be if you were being stalked in most western countries. It’s annoying, but there’s no need to feel intimidated. It’s just another bloody idiot looking for a friend. Time to be comfortably and obviously fed up. You’re trying to be polite but this is clearly an imposition and hiding it only makes things worse.
Sales people learn to ‘take control’ by choosing the ground for any encounter. Deciding who stands/sits where is a good start. Climb a stair or something then turn around to confront your stalker.
Weirdo: Is your name Godzilla?
SAF: What? (incredulous)
W: You look like my friend Godzilla
SAF: Sorry, you have the wrong person. My friends know what I look like. (incredulous and offended)
W: Will you be my friend?
SAF: Why? (hostile)
W: I want to practise English.
SAF: Teaching is my job. I charge NT$1000/hr. (straightforward)
W: I can teach you chinese.
SAF: I have a professional teacher. Are you a professional teacher?
SAF: (shrug) Thank you. Goodbye.
W: Can we be friends?
W: I said…
SAF: (point to the nearest female) Be friends with her. Why are you asking me?
SAF: I don’t talk to strangers. Make friends with someone else. Goodbye.
You could also try making up some card describing yourself as a freelance teacher or rent-a-friend with hefty charges and a made-up MSN name. Just hand it over and say “I’m really busy. Can’t stop. Here, take this. Bye.”
On the reverse side you could print a little rant about how rude it is to accost girls on the street and warn that it leads to violence. Label it “Free cultural issues lesson #1”