In an Imagine Spot, Dave imagines having a love life with Lucy, and one of the scenes in said Imagine Spot involves them running along a beach while laughing.
Margo giggles nervously when Antonio sweeps her off her feet on their first meeting.
At their wedding, Gru and Lucy are laughing while dancing together.
In Robin Hood (1973), Maid Marian, upon recognising Robin (who's disguised as a stork), giggles while wishing him luck.
In Hercules, Hercules and Megara tend to laugh as they hang out together and eventually fall in love, particularly in the garden scene.
This is invoked and exploited in Mulan, when Yao, Ling and Chien-Po disguise themselves as concubines and giggle as part of their act while approaching Shan-Yu's guards, in order to take them out.
In Tangled, Rapunzel giggles briefly after Flynn goes to get some firewood, and she later admits to Gothel that she thinks he likes her. The two eventually get married, at the end of the film.
In Frozen, Anna tends to sigh and giggle a lot around Hans from the moment they meet, at least until he reveals his true colours.
A similar example to the one in Mulan occurs in Kung Fu Panda 2, when Po giggles while pretending to be a female panda in order to get close enough to a nearby wolf to knock him out, which is successful.
In Monsters, Inc., we get the following exchange between Mike and his girlfriend Celia:
Mike: I just got us into a little place called, um, Harryhausen's. Celia:[gasps] Harryhausen's? But it's impossible to get a reservation there! Mike:Not for Googly-bear. [Celia giggles]
In Monsters University, when Don Carlton accidentally hugs Sherri Squibbles and tries to get his tentacles unstuck, she giggles as she introduces herself, and they eventually get married.
In WALL•E, EVE has a cute electronic giggle while bonding with WALL•E.
