Mariko desu. まり子です。I'm Mariko.
Kyou wa hitotsu no shitsumon ga arimasu.
今日は一つの質問があります。
Today I have 1 question.
Doushite nihon ni ikitai desuka?
どうして日本に行きたいですか?
Why do you want to go to Japan?
adding TAI to a verb means you WANT to do that action. See the link.
http://en.wikipedia.org/wiki/Japanese_verb_conjugations
and
http://www.timwerx.net/language/jpverbs/lesson8.htm
basic Japanese lesson question to want why タイ