Whatever you do, don't be an ass, be nice to her. Just don't be someone you're not, it'll just hurt you in the end.

Tell her that you like her, you get the feeling she likes you, and that you would like to take the relationship a step further. That way there are no mistaking your intentions, you'll know how she feels about you right away, and whatever the outcome is, you can deal with it then...just don't cry.

To sum up, basically what Studio Alex said in his second paragraph, whith my own style.

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