Hey there @limxuanhui. What type of terminal do you use? What we want is that the python i/o encoding is utf-8, not charmap. Can you please try:
Option 1: In your terminal before using rasa, try:
export PYTHONIOENCODING='utf8'
Option 2: put it as part of the command, like
PYTHONIOENCODING='utf8' rasa train
if neither of these work, can you post the full error traceback?