I translated it literally as "I am clear what he means." and it wasn't accepted. It accepted it when I wrote "I am clear ABOUT what he means." Where is the word "about translated from the sentence?
why a dative ´mir´ is used here, instead of a nominative ´ich´?
Mir is the dative of ich, but can also mean 'to me'. 'Mir ist klar' means 'To me (it) is clear'.
It's clear to me ....
For me it is clear what he means...is this alright?
why is wrong '' I am sure what he means?'