Who is "the Confirming bank" ?

Thank you for your answer, but the answer of only one hand talk about banking credit and a letter of guarantee unless otherwise stated in the question, because the question includes the assertion in a range of areas, not just the area of the bank guarantee

Bank in an exporter's country which guarantees that the letter of credit established by the importer  will be honored once the conditions therein are fully complied with. 

In documentary credit transactions, the bank which adds its own irrevocable undertaking for payment in addition to that given by the issuing bank. The confirming bank is usually located in the exporter's country.

Thanks for the invitation

Agreed with both answers given by

Mr.:Jetley & Mr.:Abdalla as well too

Bank in an exporter's country which guarantees that the letter of credit established by the importer (for the benefit of the exporter) will be honored once the conditions therein are fully complied with. The confirming bank (Also called the advising bank) undertakes this responsibility on an arrangement (called confirmation) with the importer's bank which issued the letter of credit (called the issuing bank).