YOU SAID:
Haven't I seen you before?
INTO JAPANESE
これまでにお会いしたことがありませんでしたか。
BACK INTO ENGLISH
Haven't I met you before?
INTO JAPANESE
これまでにお会いしたことがありませんでしたか。
BACK INTO ENGLISH
Haven't I met you before?
That didn't even make that much sense in English.