In my native language, we have a proverb that its word-by-word translation is:
They sowed 'if' (as if it was seeds and they had sowed it in the ground), but it didn't grow.
It means, make sure that you've arranged and prepared everything to make something happen and don't wait and wish that everything would go well if something else happens. In other words, never say,"everything will be fine, just if something else happens".
A: Hey John, do you think you can pass the test?
B: Yea, I've read first three chapters. If just 70% of the questions are from these chapters, I'll be fine.
A: (They sowed if, but it didn't grow)
A: I want my money back.
B: If I harverst good crops this year, I'll pay you.
A: (They sowed if, but it didn't grow). I want my money back right now.
What can I put within brackets?