Could you explain, please, what does "to knock your confidence" mean? I know what is confidence, but the meaning of knock is not clear here. Does it mean to lessen it? I just need to translate it in my own language, and I'm not sure about the sense of this phrase. May be you could give some synonyms, or a couple of examples with this phrase?
Yes, it could be lessened; that would be the result of "knocking one's confidence.'
It can also mean to upset or jolt.