[Grammar] Knowing that I can rely on your help is a comforting thought.

[sania-baharat]

Are these three sentences OK?

Knowing that I can rely on your help is a comforting thought.
It is comforting to know that I can rely on your help.
To know that I can rely on your help is a comforting thought.

 

[emsr2d2]

Are these three sentences OK?

Knowing that I can rely on your help is a comforting thought. :tick:
It is comforting to know that I can rely on your help. :tick:
To know that I can rely on your help is a comforting thought. :cross:

In the last, I would end with "is a comfort". You could use that phrase at the end of the first two as well, with no change of meaning.

 

[sania-baharat]

In the last, I would end with "is a comfort".

The last one is wrong for the last part. You meant, If I add what you suggested, will it be OK?

To know that I can rely on your help is a comfort.

 

[Tdol]

That is OK, but the first two sound more natural to me.