Question

is it a healthy relationship for a mother to tell her child that they are not trying hard enough even when they're doing their best?

Answer 1

No, that will not help the kids self esteem later on.

Answer 2

It's not an healthy relationship between a child and a mother.

A good relation between a child and a mother is where they alway's say "Great Job" or "I'm so proud of you".

Telling a child your not doing enough isn't healthy, which will most likely effect the child's self-esteem.

A mother shouldn't say a child isn't doing hard enough, when a child is doing their best.

That being said, the answer is: It's not a healthy  relationship between a child and a mother.