A conviction or strong belief; confidence that something is true or will happen.
彼の無罪を私は確信している。
I am convinced of his innocence.
自分の判断に確信が持てず、迷っている。
I'm unsure about my decision and don't have confidence in it.
証拠を見て、彼女は成功を確信した。
After seeing the evidence, she was convinced of success.