The major problem with tomato seeds is that they are encased with in a gel pack to prevent premature germination within the tomato.
After cutting in half and scooping out the insides and getting the seeds out.
Separate the seeds from any fleshy bit of the tomato.
Add water and place in an air tight container for 5-7 days. After which ? I will let you know. Youtube videos say that the gel pack surrounding the seed will have been removed from the seed.
Van Heijningenn tomato nursery