Writing a personal email to a French

Theres a French girl I obviously want to plug, but im in the friend zone. 

I have a french grammar book, but I have no Idea how to end the email.

Normally she ends it with 'bye' or somesuch.  I want to maintain
the status quo, but dont want to look like I've already given up
on her. 

So what french word is a short and sweet way to end the mail?

I only wrote 3 sentences replying to her email which was about 3 sentences.