For an answer in terms of Bergman kernels associated with line bundles (a little bit of functional analysis is involved), see Theorem 4.2.3 in:
Berndtsson, Bo An introduction to things $\overline\partial$∂−. Analytic and algebraic geometry, 7–76, IAS/Park City Math. Ser., 17, Amer. Math. Soc., Providence, RI, 2010