[peanut123]

I say just ignore her. Why bother getting into the sticky situation of having to explain to your wife who this girl is ? Even if you pretend she's a ex colleague, your wife may be curious/jealous and ask you for more info (esp if the WL is a hot pretty girl with good assets, which is probably how she got into the profession in the first place), and you will then be forced to think up more lies.

Remember that your wife, being a woman, has her woman's intuition and can probably gauge the "relationship" between you and the WL just by observing how both of you interact, even if its just a awkward "hello" or a nervous smile.

And if this happens more than once, your wife will definitely be suspicious ( how many hot PRC ex-colleagues can a guy have anyway ? )

I think all you need to do is use your common sens