So I had an idea for getting these two solidly together. Lets say they get to Greyrock and someone there suspects Darin. Ridahne steps in to help her out. Could be that someone brazenly attacks her, or maybe if we wanna get more sinister, someone tries to sneak up on Ridahne in the night to kill her (thinking she's a guardian) in order to get to Darin? 

Idk, you got some ideas too? Otherwise Ridahne will just leave her there the next day.