YOU SAID:

if you think 13 cards are stupid your a not serious, probably.

INTO JAPANESE

たとえ13枚のカードがバカだと思っていても、おそらくあなたは真面目ではありません。

BACK INTO ENGLISH

Even if you think 13 cards are stupid, you're probably not serious.

INTO JAPANESE

たとえ13枚のカードが馬鹿だと思っても、あなたはおそらく本気ではないでしょう。

BACK INTO ENGLISH

Even if you think 13 cards are stupid, you're probably not serious.