If you are just starting out with SharePoint, then getting things configured the way you want can be quite daunting. For starters, I was trying my hand at creating a SharePoint 2013 discussions list and was surprised that the default view cuts the body of each discussion list item if it goes beyond a certain length. I am sure this is no big deal for someone who is very familiar with previous versions of SharePoint, but it actually took me a bit of searching around to figure out where in SharePoint the setting is that lets you show the full text in each list item.
Bottom line is that to show the full content of the body of each list item you’ll need to create a custom view and then edit the style of your new view to be something other than Default. For example, I chose the Newsletter style, which shows the full body text entered in a first-in-first out order. The default view cannot be edited so a custom view is necessary. I think MS kept the default view non-editable since they intend it to be used for administrative tasks such as approving new discussions and don’t want people to customize it too much beyond adding or removing columns.
Once you have created a custom view, you can get to the Modify View option under the List tab at the top left of the page when you are viewing your discussion list as an administrator. In that tab look for the Manage Views section and then click the Modify View option. Name this to be something that you can find later. You can now edit and update as you see fit. The style option is an expandable folder near the bottom of the page. Once you expand it, select an option other than the default and save your changes to see how the different settings look now. I can’t say that I really like most of the available options, but the Newsletter style seems acceptable.