Btw why can being learning English and Japanese be a bonus in dating? I mean it indeed enlarges my dating pool, but by gaining me access to the relationships with the girls in other countries, instead of making me more attractive.
My detailed answer answer:
1. The smooth communication. Some people (including the girls) think you're not smart enough, you're even "stupid" if you're not fluent in English. The smarter once can't think it in this way, but they'll admire your better language skills for sure. Let's say that if you're becoming a 6/10 J-pop-tier male after a year of gym-maxx and fashion-maxx, the language-maxx will add up to you at least a 0.10 and you'll be a 6.1/10. The more, the better.
2. More languages = more opportunities for other -maxx things -- geomaxx, jobmaxx, moneymaxx, etc. Combine them all and you'll see the greater ascending potential for sure.
3. When you learn a language, you're burning calories (speaking, writing, thinking... all these are burning some calories). For example, according to healthstatus.com, it is possible for a person to burn between 60 to 100 calories or more by concentrating vigorously while studying, writing or typing. (Yes, it's nothing special, compared with running but it's a way to get rid of some candy or little cake via just learning foreign language). You know, it's not only sports when it comes to burn calories -- study, washing, cooking, etc., all may help more or less.
4. You will be more attractive if you speak well English and Japanese, at least much more attractive, than those Chinese who can't speak any foreign language. You know that Chinese people are one of the worst in terms of speaking a foreign language, right? And this is one of the reason that foreigners (and Chinese themselves) think something like "What a stupid and/or lazy man/woman! He/she even didn't learn English!"... Imagine how better you look in the eyes of a Japanese girl (and her friends, relatives) if you speak well English and Japanese, than if you're just a Chinese who speaks only Chinese... I can't imagine how they'll (in Japan, for example, which is a society with comparatively highly educated people) perceive a Chinese who can speak only Chinese language.