If you fancy a girl, go talk to her.
Don’t use intermediaries.
Don’t do a subtle dance for three weeks.
Walk up, strike up a conversation. Be witty. Ask questions. Asking about someone’s relationship status is relatively harmless. If they are in a relationship, they will be flattered that you were interested. If they are not, you’ll get immediate feedback on whether they fancy you.
If they don’t fancy you, there is no consequence. Shy fellas seem paralyzed by the fear that they will be rejected.
Smallholder says: So what?
You accept their non-interest and move on. Without having wasted weeks (or months in the case of certain way-too subtle wannabee dictators) in fruitless pining.
The only thing you have to fear is fear itself.
Thus sayeth Smallholder.