Visitor Visa - B2

hello ,
my sister wants to tour usa through one travel company from india for 2-3 weeks. .
1)her details-single , age above 35, not working so not paying tax
2)she has some saving of 5 laks in fds n banks
3) I am sponsoring her since I m working with good financial background.
  
I guess she has to apply for b2 visa ( 10 yrs ) .what will be her chances of getting visa if we show following things .
1#she is doing baby sitting for my child( so her niece) .and so has reason to return for baby caring
2#she has to attend one workshop in india for which she has already paid and booked . so she has to return
3#she has to give exam for which she has already paid money .so she has reason to return to give exam .