#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)\*\*([\x{3041}-\x{3096}\x{30A0}-\x{30FF}\x{3400}-\x{4DB5}\x{4E00}-\x{9FCB}\x{F900}-\x{FA6A}\x{2E80}-\x{2FD5}\x{FF5F}-\x{FF9F}\x{3000}-\x{303F}\x{31F0}-\x{31FF}\x{3220}-\x{3243}\x{3280}-\x{337F}]+)\*\*"
Local $sString = "**้
็นใ **"
Local $sSubst = "<b>$1</b>"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm