I'm looking for some assistance in understanding the second line in the below as I am not quite sure what 果たせる is referring to (I know what 果たす means in e.g. 目的を果たす). I am not sure if there is something in context that I am missing or not.
To provide some basic context、the village chief wants the young ones to leave the village and see the outside world (The one currently talking is actually someone who has come from the outside world, and the village chief has asked him to take her outside with him). They ask to stay and he thought that they were only saying this because they thought it was their responsibility to stay in the village. They clear up his misunderstanding about why they want to stay in the village.