I wouldn't know

It is more polite, more diffident.

"I didn't know" is the past tense; you didnt know it yesterday

"I don't know" is the present tense; you don't know it now

I wouldn't know is mainly a politeness form. It comes from, "[If you were to ask me,] I wouldn't know."

Hi,

I wouldn't know what it means? How different from the followings? I didn't know I don't know..

I didn't know what it meant. At some point in the past, I didn't know. Just a simple statment of fact.

I don't know what it means. Right now, I don't know. Just a simple statment of fact.


I wouldn't know what it means. This also refers to right now, but adds