If I may butt in here, there
are Western women who date, and even marry, Japanese men. Don't get me wrong, there aren't
many. But they're out there.
One of my Japanese teachers in college was such an individual. When I saw a Japanese name on my schedule, teaching a Japanese class, I expected to get a Japanese person... but instead, I got a blonde named Susan, who had married a Japanese businessman years before.
Likewise, when I was a young exchange student in Osaka, I had a female friend from Hungary who dated a Japanese guy. Their relationship actually worked for a while, until she had to return to Budapest (she has since been proposed to by a Japanese-speaking Hungarian). So these two cases are proof (to me) that it isn't impossible.
The catch in both of these cases was that the male had spent considerable time outside Japan, enough to learn good English, while the female had spent considerable time in Japan, enough to learn good Japanese. This coincides with mauler's point above: that Japanese males in Japan are generally incompatible with Western females in the West simply because their upbringings have been completely different. If there's a sufficient middle ground for the couple to work from, then it's entirely possible for a foreign female to have a truly meaningful relationship with a Japanese male.