"Hot Russian spy leaves enigmatic Facebook trail." Hot is used in this context to explain that Ann Chapman is young and attractive. Enigmatic means mysterious, puzzling or hard to define (ambiguous). "The attractive Russian spy leaves an interesting and mysterious path to follow on Facebook" would be a different way to phrase it. I assume you machine translated this sentence from Chinese. I have no knowledge of Chinese characters, I only explained the English in your question. I hope that helped! Scott