I was surprised to hear the pronunciation of dye and die are the same.
I was kind of shocked to hear that dye and die are both pronounced the same.
この場合の「驚く」も surprised や shocked を使って表現できますよ。
ーI was surprised to hear the pronunciation of dye and die are the same.
「dyeとdieの発音が同じと聞いて驚きました」
pronunciation で「発音」
ーI was kind of shocked to hear that dye and die are both pronounced the same.
「dyeとdieはどちらも同じように発音すると聞いてちょっと驚きました」
to pronounce で「発音する」
ご参考まで！
カナダ 
