Popping the Question in Japanese 
After a few nights of successful yobai, your lady and her family will have expectations of marriage. To seal the deal, may I suggest one of a few classic Japanese proposals.
In place of the western cliche: “Will you make me the happiest man alive?”
毎朝、お味噌汁を作ってくれませんか。(Mai asa, o-miso shiru wo tsukutte kuremasenka?)
“Will you make my miso soup every morning?”
Miso soup is the cornerstone of any complete Japanese breakfast, and letting her know that you want her in your kitchen every morning is sure to set her heart a-twitter.
If you really want to butter her up, may I suggest the following in place of: “Will you share the rest of your life with me?”
一緒のお墓に入らない。(Issho no o haka ni hairanai?)
“Will you share the same grave as me?”
Grave plots are expensive in Japan, and she will feel so lucky to have that taken care of. Anyways, once you’ve been married and she’s popped out a kid or two, that is likely all you will be sharing.
To seriously lock that down, instead of asking: “Will you have my children?” drop this sure-fire bombshell:
私の下着を洗ってください。(Watashi no shitagi wo aratte kudasai.)
“Will you wash my underwear?”
It’s best that you both are on the same page about your expectations and presumed roles in this relationship. Japanese marriages are based on the stable ground of obligation and tradition, not the temperamental shores of romantic love. Divorce rates are low, and infidelity is high.
So there you have it; your very own Japanese wife and your very own Japanese marriage. Enjoy the miso and clean underwear and start saving for that grave plot.