Our dating style did have this kind of communication too, in declaring one's intentions. Either we've forgotten, discarded it or could be the result of a more nomadic lifestyle. I'm not a historian. I'm also from Norway, but I think this goes for most of Europe. However, grain of salt.

If a man declared that his efforts towards a girl were an intention to get married, and subsequently reneged without good cause, the local community would deem him untrustworthy. This could make him unfit for marriage but also for employment. So not declaring one's intention if pressed was suspect.

My grandmother did the housewife school to make sure she was going to be a good wife, which stems from this kind of worrying about public rejection. People didn't move around so much so your local community's estimation of you was important.

As for the Japanese practice, the country was essentially "locked up" culturally until the 2nd world war so I'm not surprised old practices are still remembered. (Again, not a historian.)