God/goodness/Heaven knows phrase spoken informal
No one has an idea.
God knows what happened to them.
God knows how long we'll have to wait here.
It is unquestionably true, certain, or certain that; it is clear that.
Goodness knows my plane is feasible. You can believe in me.
Heaven knows you were planning to go without me.
A legal matter that is very easy to solve
State something in a very strong, clear and effective way
To know powerful and influential people who can support you
If a person has the devil's own luck, he or she has extremely good luck.
A: Yesterday I won a $10 million lottery jackpot and today I won a car in a draw.
B: You have the devil's own luck.