YOU SAID:
I bet that cost you an arm and a leg
INTO JAPANESE
きっと腕と脚の費用がかかる
BACK INTO ENGLISH
I'm sure it will cost you an arm and a leg.
INTO JAPANESE
きっと腕と脚の費用がかかると思います。
BACK INTO ENGLISH
I'm sure it will cost you an arm and a leg.
That didn't even make that much sense in English.