I was playing for a while when I started to study a bit on how to get Samantha confidence up and found a good way to start the few weeks off in game.
It mainly consisted of working out till her happiness decreased to 70 or 80 and then watching tv and taking a shower and heading to bed before 20:00. After that I started getting her to get her happiness up and confidence up.
I stop around some points when she starts sweating and take a shower so it doesn't decrease her confidence(I'm not to sure if working out smelly does anything to her confidence).