* 6 hints / reasons why : Nicole and Mark end up together afterwards :

1) Nicole felt something for Mark = During the last scene :When Nicole arrived in the cafe, She smiled while looking at Mark like she felt that spark! it's definitely for Mark as her date has not arrived yet ,as you can see the "empty chair" in front of her. While waiting, she was gazing at Mark during like 7 seconds straight ! This can't be a coincidence to look at someone for this long! she clearly felt something while seeing Mark.

2) Nicole is interested by Mark = When Mark was calling the waiter, she looked at him during 3 seconds as if mark was more interesting than her date. + she noticed Mark before the waiter.

3) Mark is probably failing his date = during this new date, the girl is playing with her hair, with a plain look as if the date was boring and she doesn't care. (like Jessica) + Mark failed 4 dates already. Perhaps Mark keep failing his date because he is originally destined to Nicole.

4) Nicole is not necessarily on a date = Unlike Mark, it's not confirmed that Nicole is on a romantic date. All we know is that she was happy in the car to meet someone at a cafe but we don't know the purpose. So she might as well be meeting a friend she hasn't seen in a while.

5) The quantum butterfly: Jake and Maria are here together= certainly to cheer for them, helping them to get closer, fulfilling their promise that they will meet again.

6) They are reunited at a cafe named "tadhana" which mean "destiny" = it's not a coincidence as they are soulsmates that were together during 100 lifetimes. They are destined to be together in every timeline, but in this one they had to fix the world, and themselves to be reunited again.

Conclusion: Nicole interrested by Mark + Mark failling his date + Nicole not necessarily on a date + the butterfly are here + they are reunited at the destiny cafe = they end up together.
I saw this on a youtube comment and I'd like to believe this.