Perhaps she expected more than what she got.

She released one single in Japan and was a superstar. One. She released one full album, and broke a record. One album.

She originally released Precious which barely got attention, and then years after being one of the hottest stars in Japan EVER, she came back to the States. Exodus, let's face it, was a flop. It probably drew in maybe... five new fans? The rest were fans of her Japanese work already, and probably a good half or even 3/4 hated it.

Then she released This Is the One, and while it did significantly better than Exodus, it still wasn't the huge hit that First Love was (or the rest of her albums) were in Japan.

Perhaps because she clicked so quickly with Japan's listeners, she's having a harder time getting motivated to get noticed and click with America's?

Either way I think it's a crying shame. This Is the One is actually one of my favorite albums from her, and I would love to see more English work from her.
If she HAS been discouraged, hopefully she won't give up entirely. And if she wants to catch America's eye, she needs to at least release another single fairly soon, otherwise the people that DID notice "This Is the One" will forget about her.