My Girlfriend Is an Alien Episode 5

The romance is slow to develop but the ride is hilarious

This episode seemingly tipped the key factor that will be important for the romance in that ML still remembers Xiaoqi after a rainstorm even though he forgets all other females. On the other hand the episode closes in mixed fashion with him on a date with the stereotypical 'scheming girl' and Xiaoqi innocently trying to help him on the date because ... well. She's an alien. The two are already bantering like a married couple but it's clear that she is still too naive and he has way too many neurosis that their romance is going to be slow to develop.