This sound is from Mysterious Girlfriend X Soundboard

Mysterious Girlfriend X is a Japanese manga written and illustrated by Riichi Ueshiba. It was originally published as a one-shot story in 2004 before becoming a serialized comic in Kodansha's Monthly Afternoon magazine in 2006. The manga is licensed in North America by Vertical.
See also: Riichi Ueshiba, AT-X (TV network), Vertical (publisher), Hoods Entertainment, Josh Grelle, and Ayumu Watanabe.