It helps to show a simple example with code and output what you have explicitly tried. At a guess your console doesn't support Vietnamese. Here are some options:
# A byte string with Unicode escapes as text.
>>> x='\u0110\xe8n \u0111\u1ecf n\xfat giao th\xf4ng Ng\xe3 t\u01b0 L\xe1ng H\u1ea1'
# Convert to Unicode string.
>>> x=x.decode('unicode-escape')
>>> x
u'\u0110\xe8n \u0111\u1ecf n\xfat giao th\xf4ng Ng\xe3 t\u01b0 L\xe1ng H\u1ea1'
# Try to print to my console:
>>> print x
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\dev\python\lib\encodings\cp437.py", line 12, in encode
return codecs.charmap_encode(input,errors,encoding_map)
UnicodeEncodeError: 'charmap' codec can't encode character u'\u0110' in position 0:
character maps to <undefined>
# My console's encoding is cp437.
# Instead of the default strict error handling that throws exceptions, try:
>>> print x.encode('cp437','replace')
?èn ?? nút giao thông Ng? t? Láng H?
# Six characters weren't supported.
# Here's a way to write the text to a temp file and display it with another
# program that supports the UTF-8 encoding:
>>> import tempfile
>>> f,name=tempfile.mkstemp()
>>> import os
>>> os.write(f,x.encode('utf8'))
48
>>> os.close(f)
>>> os.system('notepad.exe '+name)
Hope that helps you.