You stated:

It is possible that he/she forgets about that edit and miss even the comment that sometimes are given with the rejection.

Unlikely, as the next time they submit an edit they will see a warning about the last reject:

Kevin implemented this as described below. One rejected edit will produce the following warning:

That links back to the last edit that was rejected. If the editor never gets any edits approved, they'll see this every time they go to edit, until they're banned. If some are approved but many are rejected (see details below), they'll get a more noticeable warning:

...Which links to /users/current?tab=activity&sort=suggestions. We're not currently indicating whether these have been approved or rejected on that page. UPDATE (December 10, 2014): We now show suggested edit outcomes on that page (pending, approved, or rejected).

Finally, there's an in-between warning that'll appear for folks who get most of their edits approved but have a few declines (see below for details):

Again, this links to the viewer's suggested edit history, and should allow conscientious editors to find past edits even when their most recent edit was approved.

Source Decision on rejected edits should be displayed as a notification to the editor

You stated:

It is possible that he/she forgets about that edit and miss even the comment that sometimes are given with the rejection.

Unlikely, as the next time they submit an edit they will see a warning about the last reject:

Kevin implemented this as described below. One rejected edit will produce the following warning:

That links back to the last edit that was rejected. If the editor never gets any edits approved, they'll see this every time they go to edit, until they're banned. If some are approved but many are rejected (see details below), they'll get a more noticeable warning:

...Which links to /users/current?tab=activity&sort=suggestions. We're not currently indicating whether these have been approved or rejected on that page. UPDATE (December 10, 2014): We now show suggested edit outcomes on that page (pending, approved, or rejected).

Finally, there's an in-between warning that'll appear for folks who get most of their edits approved but have a few declines (see below for details):

Again, this links to the viewer's suggested edit history, and should allow conscientious editors to find past edits even when their most recent edit was approved.

Source Decision on rejected edits should be displayed as a notification to the editor

You stated:

It is possible that he/she forgets about that edit and miss even the comment that sometimes are given with the rejection.

Unlikely, as the next time they sumbit an edit they will see a warning about the last reject:

Kevin implemented this as described below. One rejected edit will produce the following warning:

That links back to the last edit that was rejected. If the editor never gets any edits approved, they'll see this every time they go to edit, until they're banned. If some are approved but many are rejected (see details below), they'll get a more noticeable warning:

...Which links to /users/current?tab=activity&sort=suggestions. We're not currently indicating whether these have been approved or rejected on that page. UPDATE (December 10, 2014): We now show suggested edit outcomes on that page (pending, approved, or rejected).

Finally, there's an in-between warning that'll appear for folks who get most of their edits approved but have a few declines (see below for details):

Again, this links to the viewer's suggested edit history, and should allow conscientious editors to find past edits even when their most recent edit was approved.

Source Decision on rejected edits should be displayed as a notification to the editor

You stated:

It is possible that he/she forgets about that edit and miss even the comment that sometimes are given with the rejection.

Unlikely, as the next time they submit an edit they will see a warning about the last reject:

Kevin implemented this as described below. One rejected edit will produce the following warning:

That links back to the last edit that was rejected. If the editor never gets any edits approved, they'll see this every time they go to edit, until they're banned. If some are approved but many are rejected (see details below), they'll get a more noticeable warning:

...Which links to /users/current?tab=activity&sort=suggestions. We're not currently indicating whether these have been approved or rejected on that page. UPDATE (December 10, 2014): We now show suggested edit outcomes on that page (pending, approved, or rejected).

Finally, there's an in-between warning that'll appear for folks who get most of their edits approved but have a few declines (see below for details):

Again, this links to the viewer's suggested edit history, and should allow conscientious editors to find past edits even when their most recent edit was approved.

Source Decision on rejected edits should be displayed as a notification to the editor