Sounds good, although I struggle a little to see a direct end user for that..if that would be singles.city, I can imagine dating site. For singular, I am not so sure.
Anyway, it might serve as brandable, as name is nice and memorable .City sells nicely, so it can fetch 1-3k in 2017. But..probability of this happening is rather slim (if you have portfolio of 100 very good domain new gTLD domain names, you usually sell 1-2% of them/year..so you can calculate the probability from there)