When I first read it I thought the last word was "karada" (body, if not wrong). But I suppose it is "kara" and "da" (from desu).
But, although it is not the topic now.. I don't understand the "no wa" structure linking both sentences.. I think this "no wa" is to substantive the verb?
日本へいきたいのは恋人 (boyfriend) にあいたいからだ