She said with great sadness to me. The candid and painful truth gradually revealed.- Here, I'd use spoke. In the second sentence, I'd change it to 'was gradually revealed'.
Viet Nam in the 1980s has been- was
its remaining impacts are still easily realized up to now- and the impact can still be felt
They do impede- It does impede
from their government- from the governement
wants to derive respects & admiration from others- want respect and admiration from others
this characteristic prove - proves
Relief supplies, however, has- have...are