Before the world knew him as a notorious alleged killer of young women, Melody Granadillo knew Joran van der Sloot as a personal prince charming.
"He was amazing. ... He was romantic," the 23-year-old said of her former boyfriend and first love, in an exclusive interview to air on "20/20" Friday. "It was very playful, very honest. We could sit and talk for hours. We liked looking into each other's eyes."
The couple met at a mutual friend's birthday party in Aruba in October 2003 and dated for seven months. The 16-year-old quickly fell head over heels in love with 17-year-old van der Sloot -- the man she calls "Chi Chi" or "Mr. Wiggles."
In the "20/20" interview, Granadillo describes van der Sloot as sweet and charming. She recalls how for her 17th birthday, he surprised her with her favorite candy.
"I told him I liked red Skittles ... and what he did was he made this vase at school, went and bought a lot of Skittles packets, he took all the red ones out ... and as a present I got a vase full of red Skittles," Granadillo said. "He did things like that ... he was real thoughtful."
The teen saved everything from her dashing Dutch suitor, including a diary they shared, filled with pages upon pages of pictures, cards, emails and love poems. Granadillo licensed a selection of these materials to ABC News.
In the diary, Granadillo, who said they discussed marriage and kids, writes of one of their first sexual encounters: "We fooled around a lot. He wanted a lap dance. I barely gave it. It was an awesome night. Romantic and fun. Also, I gave him a hickey."
But while van der Sloot was playing Romeo, Granadillo says she learned that their romance was built on a web of lies.
"He would lie for no apparent reason at all ... and if you caught him at it ... he would double down and be even more serious about the story," she said.
Granadillo claims he told her that he was also a virgin, but was really a promiscuous playboy who cheated on her with multiple women.
Despite their break-up, Granadillo never lost contact with van der Sloot -- staying in touch through the disappearance of Alabama teen Natalee Holloway and up until his now-infamous trip to Peru.
With van der Sloot now awaiting trial in a Peruvian prison, Granadillo says while she doesn't regret their experience together, the man whose eyes she loved looking into is long gone.
"It's not connectable. You can't connect that. It's not the same person," she said. "You see he's hurt. You see he's in trouble."