The true value of a therapist (at least in traditional talk therapy) is a non-judgemental sounding board. That sounding board then prompts you to explore issues further, but it's you that's doing the work.
With that in mind, two things:
Therapy is an ongoing process, and a relationship. It's very rare that a "quick hit" of 6-12 weeks is that effective, although short term traumatic incidences like deaths in the family see a lot of benefit through the crisis points.
The subject has to want to participate and work on their issues. Wanting to buy therapy for your wife is very noble, but working through her issues will take time - potentially years - and can be exhausting, frightening and challenging. She's got to want to do it, and will need patient support if she does.
Good luck!