The project's success was down to sheer dinkum from every volunteer.

She's a dinkum friend who would drive three hours to help without asking for anything in return.

He's straight dinkum, so you can trust him.

She's a straight dinkum friend who never lets you down.

I fair dinkum can't believe she won the competition.

She offered a fair dinkum apology and immediately set about fixing the problem.

If you want the dinkum oil, ask him - he won't sugarcoat anything.