Open Safari, hit the 2 squares bottom right, the screen should look like this:
Hit new page, a blank white page should open, now hit the 2 squares again, screen should look like this:
now leave the white page but swipe across to all other open pages hitting X on each of them until you are left with just the white page. Close Safari without looking at any further websites. Now open Settings, scroll-down to Safari and again scroll down to reveal the clear buttons.
Hit each of them and your browser history should be clear or as clear as you can get it.
To be sure I then go into Safari, hit the bookmarks icon (looks like an open book) top of the list should be history, click on it, if it's empty great if not hit clear bottom left. That's unfortunately all you can do..