YOU SAID:
Yeah, I'm a gamer. How could you tell?
INTO JAPANESE
俺はゲーマーだどうしてわかるの?
BACK INTO ENGLISH
I'm a gamer. How do you know that?
INTO JAPANESE
私はゲーマーです。どうしてわかるの?
BACK INTO ENGLISH
I'm a gamer. How do you know that?
That didn't even make that much sense in English.