[Grammar] The problem is that...

[sky3120]

Hello. I have a question about usage of a comma. I saw this sentence, 'The problem is, I hate him.' But I would say that 'The problem is that I hate him.' So is it okay to change 'that' to ',' in the sentence ?

Thank you as usual in advance.

 

[5jj]

Both are fine.

 

[sky3120]

Thank you and "I will tell him that I met her" can be written as "I will tell him, I met her"?

 

[emsr2d2]

Thank you and "I will tell him that I met her" can be written as "I will tell him, I met her"?

No. No comma is required. "I will tell him I met her" is fine.

I will tell him, I met her = Information 1) I will tell him and (unconnected) Information 2) I met her.

 

[5jj]

Thank you and "I will tell him that I met her" can be written as "I will tell him, I met her"?

You are doing what seems to be getting more common in this forum - taking a response to one question, and jumping to the idea that a rule has been established that will cover different, if similar looking, constructions. Not only is the comma not required there, it is wrong.