To me, you are definitely not somebody else's shadow. You are unique in my heart. (比較口語(yǔ)化）
或：I see you as unique, not as someone else's shadow. （把次序換了一下,且變得稍微簡(jiǎn)練了些,但意思不變）
I love you as someone who is absolutely unique and without a trace of anyone else's shadow.（并不算直譯,但意思還在,且比較華麗）
另外,ls二位的語(yǔ)法都錯(cuò)了.不過前面二位的說(shuō)法改正成：You are definitely not the shadow of any other person, but the only one in my heart,雖不是最好的,但還是可行.
第三位基本上無(wú)可救藥了... 但勉強(qiáng)改成：You are my most beloved, not a shadow of anyone else,倒也不錯(cuò).