That's great, in that case you should take your pick of any of the T1 cities except for Shanghai and Beijing. I guess the other factor I forgot to ask about is money.
Shanghai is incredibly expensive in every sense but especially in rent. Your dollar will not go nearly as far. Girls will be richer and harder to impress. You will have to budget more, live in a smaller and more distant apartment, and sacrifice opportunities for budget reasons... all this unless you have a big pile of money to spend. Every other city, especially T1.5s like Chongqing, are much more affordable and still rife with opportunity. Obviously I'm a bit biased on this one though, some people would much rather live in the highly cosmopolitan and sophisticated Shanghai even if they can't be big spenders. It is also the only city in the country (+ Hong Kong) where you can actually use English and get away with poor Mandarin.
Beijing seems kind of ass from everything I've read on it. It's the second or third most expensive city in China (cheaper than Shanghai, similar to Shenzhen) but its local governance is very CCP with all the tight controls such an administration brings. It seems very culturally muted. I wouldn't choose it over any other T1 or T1.5.
My recommendation would be Chengdu or Chongqing, probably in that order. You're going to have to buckle down in learning Mandarin or else daily life will be a struggle and you'll be locked out of >80% of dating opportunities. Just like Japan or Korea, girls do speak English and are excited to speak it with you, but it's a give-and-take thing where you need the local language to fall back on as a safety blanket for her. I would recommend getting to at LEAST HSK1 level before touching down in China.
