He says he'll always love me 'deep down'?

Last night we had an argument and he said that he didn't know if he loved me or not but he know in his heart he did or something.. Which hurt alot ofc, i love him so much and we've been together for a year. He told me later that he did love me and that he always will 'deep down' what does that mean? Im still not convinced that he does properly still cause before that i asked him if he was sure that he did love me and he told me not to ask questions that i dont want to hear the answer to :( thanks x