[RadioKid]

To emphasize your reason, you can use "なぜなら" or "というのは" after the main sentence. I often listen foreighner use "なぜなら". It would be fit English language structure (I mean it does not sound natural Japanese).

Because Japanese language has no direct coresspondance with the word "because", some time you can throw away the ".... because ...." structure. I mean "<MAIN> because <REASON>" structure would be realized in various styles.

そのお人形を買ってあげたのは、あなたが欲しいといったからなのよ。

And, also

あなたが欲しいと言ったから、そのお人形を買ってあげ たのよ。

has enough emphasize on the reason (I think).