How do you guage someones interest?

Level 2
What question can you ask to see if someone is a serious buyer or just window shopping?

Here is my default question when someone messages me showing interest:

"Thank you for taking time to show your interest, are you ready to make an offer and buy or just browsing?"
Community Helper
I usually gauge interest by how fast they respond and how fast we can agree on a meetup. I usually ask them if they are indeed interested. Most of the time they dont answer.