'I love her who is wearing the red shirt' would read better as: I love the woman wearing the red shirt. Although it is not really possible to love someone wearing a red shirt. The sentence you have given implies you do not know the woman wearing the red shirt. If you like how the woman wearing the red shirt looks, you might say: I think the woman wearing the red shirt looks beautiful. You can imp
I wrote that reply and was talking on the phone at the same time - there are a few errors. The last sentence should read 'I love WHEN she wera her red shirt'. I should have also written ...I feel you would need to make that fact KNOWN not 'know'....sory!