Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
likelihood [ˈlaɪklɪhud] n вероя́тность f
in all likelihood по все́й вероя́тности
there is every likelihood that ... о́чень вероя́тно, что ...
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.