NET

18 Against hope Abraham believed in hope with the result that he became the father of many nations according to the pronouncement, “so will your descendants be.”

Darby

18 who again^D8022st hope believed in hope to his becoming father of many nations, according to that which was spoken^D8023, So shall thy seed be:

Darby Bible Notes

in - Or 'with,' epi. It is the state or condition of his mind in believing. see ch. 10.19 and 1Cor. 9.10, and Note at 2Tim. 1.12. spoken - Gen. 15.5.

KJV

18 Who against hope believed in hope, that he might become the father of many nations, according to that which was spoken, So shall thy seed be.