Well, this can be pretty confusing at times. Both sentences are perfectly correct. The first one, where you used the past simple, means that he accepted her in the past, at one particular moment. And that's it. We don't know what happened after that because we don't have any information about it. It is just something had happened in the past and we do not know if it is still true, or whether someone is telling a story about it, narrating through the past simple tense. The second sentence, where you used the present perfect, suggests that he has accepted her in the past and that is still true. He still accepts her today, at this very moment. It has been true since the day he had accepted her.
I hope I made it a bit clearer for you :)