Export - exported video but didn't look like the preview within Adobe Premiere
First of all, if you are using proxies, don't use Proxies, and see if that solves the issue.
If it doesn't, move on to the next step below.

The issue is that there can sometimes be a problem when the final export doesn't match the sequence created by dragging the source clips onto the timeline.

When creating the Sequence, instead of dragging clips onto the Timeline directly, create a new Sequence in the Project bin while at the Assembly page (by clicking on File option in the menu bar, New > Sequence, click on the Settings tab in the following dialog box, then change the Editing Mode dropdown to Custom, whic lets you edit all the settings), that has the exact resolution and FPS settings as you want in the export. Then double click this new Sequence to load it onto the timeline. Drag the clip onto the timeline and when Premiere asks if you want to change the Sequence settings to match the clip, select No. Now transform the clip from the Edit tab. Rotate and zoom or crop, whatever your operation is. This should hopefully solve the problem.