Presumably the questioner is not related to the spouse he is planning to marry. There is always a small risk of having a child with deafness even if there is no family history of deafness (1 in 1000). In this case the risk would increase somewhat, but this would be dependent upon whether the couple carry the gene for deafness.
I would recommend that the person who is deaf should be tested for the connexin 26 gene mutations, and if the mutation is found then the prospective spouse should be tested for the same mutation, to see she carries the mutation. The risk to child would only be there if the questioner himself is also a carrier of the gene defect for deafness.
They should consult a geneticist for more definite information.