How to go to Johor Bahru from langkawi? (Kuala Lumpur)

Merry Christmas everyone!
Im Chinese, planning a trip to Langkawi and Johor Bahru for business trip, but they seems so far from each other, as i never been to Malay before, anyone can advise the safest & fastest way to JB?I have thought about flying from Singapore but it doenst make much sense as i still need to travel from JB to Langkawi...the best seems to be find a way to travel to JB from Langkawi directly.

And, will it be a safe trip?My malaysian friend told me be careful about bla bla bla.. now im scared...