Legal Question in Landlord & Tenant Law in California

In what situation/ courtroom, discussion with tenant, etc.? Normally the burden is on the person who can best prove the fact to do so; usually the tenant needs to prove that they did pay the rent by showing a receipt, money order stub, deduction from their checking account corresponding with their check book showing the rental payment that day, etc. The landlord stating the rent has not been paid is some evidence of it not being paid; most judges trust landlords more than tenants, based upon the greater number of untruthful tenants versus landlords..