Trailing slash in url

I got some problems in Console as trailing slash and without trailing slash makes duplicate content. Can you tell me which should I choose the best structure.
domain.com/title
or domain.com/title/
or https://www.domain.com/title
or
https://www.domain.com/title/

it is on wordpress CMS and built long back however lost rank in serp from last 3 months.

 

"/title" means the page.
"/title/" means the main page of section.
The difference is the same as between a folder and a concrete file in Windows.

 

Leave off the last trailing slash. To a bot I believe it means "index.html" of the next folder.

 

Thanks for your replies, Google console detected as it is duplicate so how can I remove the non trailing slash urls from Console.

 

The most easy way do it via 301 redirect in .htaccess.

RewriteEngine On
RewriteBase /
RewriteRule ^(.*)/$ /$1 [R,L]

Code (ApacheConf):

I hope it helps you.