Wordpress HTaccess and Google Analytics Help

Need some quick help from someone who has good knowledge of Wordpress / Redirection / HTaccess files / Google Analytics.

Problems:
- When people visit pages of our website, i.e. website.com/test/ - the URL displayed is website.com/test (removes trailing slash)
- Sometimes people visit and the page cannot be found due to redirect problems (such as when we edit a WP post)
- Google Analytics reports different views for the same pages with and without slash (see screenshots)

What we need:
- Clean URLS on the website, with no duplicate pages (so pages without slash will forward to pages with slash all the time)
- Redirection setup so old indexed URLs with Google etc automatically forward to these new pages
- Google Analytics problem sorted