我是中國人, 講國語當然不會有問題啦 ~ translate to English

我是中國人, 講國語當然不會有問題啦.

I am a Chinese, speaking Pudonghua (Mandarin) would not be a problem for me.
or

As a Chinese, I'm sure can speak Pudonghua fluently.

I am a Chinese, Manderin probably will not be difficult for me.

I'm Chinese. Speaking in Mandarin of course is not a problem for me.

2008-06-13 15:05:13 補充：
再輕鬆啲:

I'm Chinese. To speak in Mandarin? You bet！

im chinese, n my mandarin is not a matter to me