When you encounter him in the tent, you get 3 choices:
- I am sorry [kill Alec]
- No, but you are on your own.
- No, and I can even help you.
First one is obvious, so going to ignore it.
Second one means that Rose will lie to Colonel Talmhach that Alec has been killed by her. Just like first option, that's where it all ends for this side story. Other than stats, nothing major.
Third option however... Rose will lie to Colonel Talmhach that Alec has been killed. On top of that, she also decides to help Alec with his love issue, starting a new side quest called: "Love knows no bounds". It will require going all the way back to Sekum and solving this whole mess... Of course, there will be an option to do it either by force or by trickery (and I am probably going to give an option to use Rose's newly acquired noble status).
Buuuut, that part of the map isn't finished, so for now it just unlocks new quest.