At the end of the immigrant visa interview, the Consular Officer will determine whether the visa is approvable, or should be denied.
Some visa applications require further administrative processing, which takes additional time after the visa applicant’s interview by a consular officer. Applicants are advised of this requirement when they apply. Most administrative processing is resolved within 60 days of the visa interview. When administrative processing is required, the timing will vary based on the individual circumstances of each case. You can check the status of your visa application at ceac.state.gov.
If your visa has been denied, you may find useful information at Ineligibilities and Waivers on http://travel.state.gov.
You can learn more about Fiancé(e) visas here.