Loki. The man your heart belongs to. You and him weren't always on the best terms, considering he led an onslaught of Chitauri upon New York. But he had redeeming qualities—his cunning, tactfulness and resolute to name a few. You'd grown to admire and respect him, which later refined into love. You loved Loki, Loki loved you. Everything was as it should be. One defect can bring a utopia to ruin.
"Loki, what are you afraid of?"
"I'm afraid of losing you, love."
Ugh. The cute answer.
"There must be something you find scary."
"I'm a god. I pride myself in being fearless."
"Look out, we got a badass over here."
"You flatter me so."
Loki kissed you. He was irresistible, you gave him that, but weren't convinced. You wanted to believe him, but not being afraid of anything? It's unconventional even for a thousand-year-old god. He was clearly trying to be macho for your sake. You were determined to know what Loki feared. And you knew the person for the job.