The regex works for normal, strong text does not affect.
I recommend you this page as tutorial to start: https://www.rexegg.com/regex-quickstart.html
and this one to test your regex: https://regex101.com/
There is not a regex code generator (or at least that I know) this is like programming you have to learn little by little.
Anyway if you need help with any regex you can contact with me.