There are so many different paths but I am going to assume you mean at the summit.
I actually do think Jenneth loves the MC. I think she is trying to save the entire world and having seen many possibly futures thanks to the resources of the Triple Chalice, in Jenneth’s words:
*label allTheFutures
"In all the futures I have learned of thanks to the resources of the Triple Chalice... I never saw one in which the two of us were together and it ended well for you. Or... Or for the Western Peninsula."
*fake_choice
#"And do you trust those futures?"
She cannot contain her emotions, and for the first time in your life, you are sure she is being completely honest with you.
"As much as I trust my love for you..." the woman says, with tears in her eyes.
*goto notSurprised
#"I must admit, that was not the reaction I was expecting from a marriage proposal."
She cannot contain her emotions, and for the first time in your life, you are sure she is being completely honest with you.
"I hope you know I do this out of love," the woman says, with tears in her eyes.
*goto notSurprised
#"Then let it all end with a rain of fire from the cursed stars, for I will have no reason to live if you are not by my side."
She cannot contain her emotions, and for the first time in your life, you are sure she is being completely honest with you.
"You need to live. As much as I need to die..." the woman says, with tears in her eyes.
*goto notSurprised
Anyways, in answer to your question it requires either social > 60 or an unmarried female MC can quote Jenneth pointing out there is no one left to oppose the MC after asking Jenneth to marry the MC.
EDIT: Oops. I misinterpreted what was meant by good ending… I apologize for that @lexa . I guess I was applying what I would consider to be a good ending instead of how it was defined 2 posts above which is what was being referenced. So as far as killing everyone, it helps to wear armor and have your back to the wall unless your combat skill is very high (70+). The choices are different depending on whether Sartham is still alive, but Jenneth merely watches the fight unless your MC tries attacking her first. If you are only facing Daedros, doing something “unpredictable” helps.

