Place it at the very end of a confession or anniversary edit, after an oh my god wow reaction, then follow it with kids cheering for a payoff that closes the sequence on a celebratory note instead of cutting away.
关于此声音
This clip is a short spoken voice line that says the words I love you in a soft, affectionate tone. It feels warm, tender and a little over the top in a sweet way, so even a simple reply sounds sincere, romantic and hard to ignore for the person hearing it.