They *might* be friends... for now. No busy man would casually stroll around with a woman he isn't interested in. It's too much of a coincidence for Ling to have a couple of days of vacation in Korea, *alone*, that conveniently aligns with Win's schedule. And Korea is too big for them to just happen to be in the same place. They were likely in constant communication, which allowed Ling to know his location and ask for a casual walk (as Win mentioned during an interview when he was asked about Ling). I CAN BE WRONG.
Very good answer Phi...❤ . He is very intelligent and diplomatic, he knows how to express his thoughts to people. Whatever is his sexual choice we have no right to judge him 🌈 .