I think we all deal with some sort of confidence issues, so you are not alone there. Don't beat yourself up, talk it out with your subbie and see why he or she is feeling like one attempt is enough to quit after. If they realize that you are new to this, then hopefully you both can work out what went wrong and fix it together. If they are new as well, they may have felt like they failed and don't want to dissapoint either. I hope you guys can give it another go, many in fact lol. Just like most things in life,sometimes things happen and you make mistakes. Take them as they come and learn from them. =)