English Translation
It was stupid of me to believe that!
Hmm… maybe:
I didn’t think I believed that either.
It was stupid of me to believe that!
Hmm… maybe:
I didn’t think I believed that either.
@mike-lima
それを信じるとは私も思わなかった is more likely to be interpreted as “It was a big surprise even to me that he/she/you actually believed it”. – The believer is not me, but someone else.
“It was stupid of me to believe that!” in English would be あんなことを信じ込むなんて、私ったらなんてバカなんだろう! You can replace 信じ込むなんて with 信じるなんて, but 信じ込む is much stronger, and it makes a good contrast to “now I see how stupid I was”.
Ah! that makes more sense, thank you!