pashya:
she will get the leave for around 1 month for sure, but now during 2nd time if she shows the leave certificate, will it be effective?... i mean won't they think that she had said that she will resign and now this time she is showing the leave certificate... i mean will the leave certificate really be effective?
what about taking the formal obligation letter from our family friend... will it help?
1) Stating the "plan to resign" bit to the visa-granting authorities was probably the worst possible move one could have taken.
Knowing what the consulate does at this time, they might honor the change in circumstances, wherein they see a better chance of your wife returning back to India to her job.
2) The formal obligation letter might be useful, especially if your family friend is in the same city as yourself. If that was tried for the first interview, it would have been the perfect option.
3) As another poster suggested, you can try to get an obligation letter on your own. Even if you build up a significant bank balance, I suspect the lack of a steady income might work against you.
4) If you have friends/family in another EU country (say France), your wife can try getting a tourist visa for that country and can travel over to DE.
Good Luck!