need to – нужно, надо.
She needs to lose her weight.
I needed to revise before my exam.
don’t need to/needn’t – не надо, не нужно (нет необходимости делать что-либо).
She doesn’t need to lose her weight.
You needn’t apologize, you did nothing wrong.
You won’t need to pay, it’s free.
He didn’t need to hurry.
They needn’t have worried because everything was ok.
There + be + need to – нет необходимости или потребности.
There is no need to worry about, they’re already here.
There was no need to call him; we were able to do it ourselves.