Justine is a great name! Not too common, sounds a bit like "Justice" but isn't so on-the-nose, the -ine ending is nice... I can't think of any real objections to it.
Please rate my personal short name lists (the latter includes combos):
www.behindthename.com/pnl/69381www.behindthename.com/pnl/69381/91835 (updated)
http://greens-end.myminicity.com/env