becomeとturned intoの違い

becomeとturned intoはどちらも「～になる」ですが、ニュアンスの違いがあります。

becomeは性質や状態が変化すること。
turned intoは外見的な形状が変化すること。

よって、She has become a beautiful womanは可能だけど
She has turned into a beautiful womanは不可。

逆に、The bank has turned into a restaurantは可能だけど、
The bank has become a restaurantは不可。