Upvote:3
Form I-134 would not be appropriate. It is filed for those asking to be paroled into the US, or potentially for visitors extending their stay. It is not filed to support a visa application.
It appears that the officer is considering the facts and circumstances of your spouse as risky. She is unemployed, recently moved to a new country (i.e.: can easily move again), recently married (i.e.: may have potentially gotten an immigration benefit due to the marriage and got disappointed and is now looking elsewhere), and has strong family ties in the US (i.e.: can easily find support and shelter once in the country). It is understandable why her visa application was denied.
I don't think there's any point reapplying if there's no change in circumstances.