How do you justify simulation results when experimental validation is not possible?

In several power electronics and antenna projects, building a full experimental prototype is too costly or physically impractical, so reviewers ask for validation we cannot provide.

I usually lean on convergence studies, comparison with published measurements, and sensitivity analysis, but I am never sure how much is enough.

How do you convince reviewers that a simulation-only result is trustworthy, and what evidence do you put in the paper?