The Collaborative International Dictionary of English v.0.48:

De bene esse \De be"ne es"se\ [L.] (Law)
   Of well being; of formal sufficiency for the time;
   conditionally; provisionally. --Abbott.
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

DE BENE ESSE, practice. A technical phrase applied to certain proceedings
which are deemed to be well done for the present, or until an exception or
other avoidance, that is, conditionally, and in that meaning the phrase is
usually accepted. For example, a declaration is filed or delivered, special
bail put in, witness examined, &c. de bene esse, or conditionally; good for
the present.
     2. When a judge has a doubt as to the propriety of finding a verdict,
h(, may direct the jury to find one de bene esse; which verdict, if the
court shall afterwards be of opinion it ought to have been found, shall
stand. Bac. Ab. Verdict, A. Vide 11 S. & R. 84.