"I'm in love!" she gushed. "I just had my five month anniversary yesterday."
"We went out to dinner and we did puzzles because I love doing puzzles lately. He brought me like three special cool puzzles that are like 3D and we spent the day just chilling," she shared of how they marked the special occasion. "It was awesome."
Trainor and Sabara may have been dating for five months, but the "Lips Are Movin" singer says she knew almost instantly that she was in love with the 24-year-old actor.
"It was pretty right away," she gushed. "I've never been treated so nicely from a guy…he showed up to our second date with a rose in his hand and I was like, 'Oh, you're a movie, awesome.' I was like, 'You're the one!'"
While Trainor's not exactly ready to walk down the aisle, she did admit that the former Spy Kids star has inspired a few love songs.
"I actually made him write some songs with me, so we've collaborated," she said. "It's fun to have someone that understands what you're doing and he loves artists, so he loves getting to see the behind-the-scenes."
See more on Trainor and Sabara's adorable relationship in the video below.