So I took my sister driving the other day so that she could get in some "seat time" before her drivers test. SHe was super nervous whne we started and by the time we were done she was really confident--how can one without confidence insipre it? The next day my Mom took her to the test and she did not pass. Now I feel REALLY bad...like I let her down somehow. I know that she wanted it really bad and I have guilt. 
sometimes (at least here in ny) they take points off for stupid stuff like not looking in your mirror for a specified number of seconds, and slowing down too much for making turns... it's impossible to know what they're gonna get you for. it depends on who you take the test with and what kind of day they're having, it seems...
anyway, i thought your question "how can one without confidence inspire it?" was fairly interesting... it just does happen like that sometimes, doesn't it?
alot of the times (or at least in ny) they don't pass people on their first time with the road test.
i think i know ONE person who passed the first time - and my friends aren't bad drivers *shrug*
as far as the ex goes, yeah. i mean we were best friends since before we started to date so that friendship means a helluva lot to me. he has a new girlfriend and i couldn't be happier for him.
have a good one, and don't stress too much about yr sis.
xo