First look at their business scope. You can check the management measures of financing guarantee companies of seven ministries and commissions online. If the guarantee company operates beyond the prescribed scope, it means that it is illegal and certainly not standardized.
The second is to look at the quality of their personnel. If employees only want to complete the business, regardless of risks, they will definitely take action in the short term, which will not be much better.
The third is to look at their charges. At present, the charging standard of general guarantee institutions is half of the bank's loan interest rate for the same period. If the charge is too high, the designation is irregular.
Through these three points, you will definitely distinguish between good and bad.
I hope it helps.