-> when any user comment on my page, an admin not receiving conformation mail to approve
-> and by deactivating jetpack comments, comments are directly approved and visible on my pages
Jetpack won't help you manage such options. Email notifications and moderation settings can be managed by going to Settings > Discussion in your dashboard, and Jetpack doesn't change any of these settings.
Users are unable to comment on my pages/posts it showing nothing after posting a comment comments mails are not going to admin
Could you post your site URL here so I can try to post some test comments?
If you want it to remain private, you can also contact us via this contact form: