Martha loved Jesus - of that there is no doubt. But it was hard for Martha to just sit still and listen. She listened while doing, but this led to missing valuable lessons from the Lord. It caused her to be resentful of Mary, who sat and listened to every word Jesus spoke. (Luke 10:39-40)
If you skip ahead to the end of Martha's story, you will find her still serving (John 12:1-2), but here we see a change in her heart's attitude. By this time, she had witnessed the resurrection from the dead of her beloved brother, Lazarus. Here in John 12, while she is still serving, we see a softer Martha. We see her, not as a busy, bustling servant, but as a listening servant. What changed? What made that difference in Martha? The rebuke she had received from Jesus the first time He had ever visited her house? Maybe. I believe the real change happened the day Martha met Jesus on the road to her house, after Lazarus had died. (John 11). She accepted Christ for Who He was. In other words, I believe Martha got saved.
Oh, she was still the opinionated Martha we saw in Luke 10, but here in John 11, we see her learning to follow the Lord - learning to trust Him completely. In John 11:40, we see the Lord remind her of His promises - gently and lovingly. While we don't have a written record of Martha's response, I believe she humbly and sweetly submitted her will to the Saviour.
John 12:2 isi the last mention of Martha that I can find, but she had obviously learned the lesson of sweet submission to the Saviour. She was still busy serving, but I believe this time she was hearing every word that fell from the Master's lips.
Martha had called Jesus "Lord" in Luke 10. In John 11, after sh me Jesus on the road, she called him "Master."