For foreign women it’s a completely different story.
Japanese men seem to expect certain things from a woman.
Maybe they also think that a foreign woman might expect from their man that he’s telling his feelings straight out several times a day, something a shy Japanese man just won’t do.
Another problem is that many of the Japanese men seem to be afraid of their English ability and thus fail to approach a foreign woman.
The cultural battle over Japanese women marrying Western men has been broadly fought for decades, but men still have that battle ahead of them.
A lack of commonality can, in itself, form a barrier.
If we look at the Ministry of Health, Labor and Welfare's figures for 20 (the most recent available), there were 236 cases where a British man married a Japanese woman in 2014, and 235 in 2015.
We'll bet a dinner and beer that the first case will far outnumber the second. However, let's take a closer look the difference for a moment.
Nobody wants to be the first (or one of the few) to stick their neck out.
When thinking about these things, Japanese men seem to prefer going the safe route and opting for marriage with someone from their own nation.
For example, it's been found that studying abroad changes one's perspectives on one's relation with foreign countries—and this study shows a correlation between studying abroad and future prospects of working abroad in the case of European students.
That says nothing directly about relationships per se, but it does weaken the barrier to spending one's life abroad with a special someone.
I’m sure you have your own and there’s much more behind all this, but that’s it for starters, I guess.