How to get the uipath business rule exception message?

i m trying to get the message in the businessruleexception to inculde in the mail and getting this error

in general it would be YourBusinessExceptionVar.Message

just debug/ stepwise / set breakpoints and follow the flow where it is broken you will receive the Reference not set exception

thanks @ppr i have been assigning the wrong exception i change it to
busexecption =exception.Message