If you want to provide your users some tools for formatting the content of their comments, why not give them a proper WYSIWYG editor? The one that is already built in to WordPress, namely TinyMCE, should be appropriate.

A question that someone might have

An answer to that question.

1.3

• Fix bug reply comment
• Thanks Andrzej Jurek

1.2

• Update insert image.
• Update mobile setting.

1.1

• Update Cursor Position.
• Add admin settings.
• Add border for TinyMCE.

1.0

• This is a very first version of TinyMCE Visual Editor Comment plugin.

1. Upload tinymce-visual-editor-comment folder to the /wp-content/plugins/ directory
2. Activate the plugin through the 'Plugins' menu in WordPress