'Let me put it this way' - is a way to be direct and to the point in an explanation. A no nonsense, no excuses explanation.
For example: - 'This month, you have spent £2,000 on home accessories, £4,200 on beauty treatments and £10,000 on a car. These costs have far exceeded your credit. Let me put it this way - you are in severe debt and need to sort your finances out immediately.'
We can also use the word 'basically' in replacement for the entire phrase.