Imo she likes him  because she takes such good care of him since little, just her bringing him the food from her cooking class and remembering it being the first korean food he ever tasted is a great example

Writer-nim is playing a little game with us, but I believe the missing words in the "do you still love him" conversation between Seok-ryu and Mo eum means they were talking about Seung-hyo which means. . . .that somehow there was more to SR's letter in the time capsule or something else happened (just WHY did Seok-ryu rush off to the USA after only 1 year in college - I can guarantee it wasn't the "oh, she got a scholarship and therefor left the family/friends for 10+ years reason).

Now, if Seok-ryu was indeed stating she still loved her  fiancée, then different answer and she doesn't yet understand her feelings w/r/t to Seung-hyo.

Regardless, it doesn't matter.  Writer-nim is writing a story where SR and SH are "soul mates" or bonded forever or "fated" or. . . .it doesn't matter.  God has decreed that they belong with each others.  and regardless of whether she currently (ep 6) understands her feelings, they will figure it out and be together in the end.  Period.  

doesn't her ex show up in the next episode (7)? after that we might be able to better assess if she still has feelings for that cheater.

She does, but she is so use to think of him only a her friend.   She has not undergo the process he already went through. The process of acknowledging...