Devarim 21:10-14 explains the law of an Eishet Yefat Toar.
The standard commentaries there indicate that she is desirable because of physical beauty. This also seems to be what the pshat is.
However, I recently heard someone insist that this is talking about a case where she is "spiritually beautiful", i.e. someone who should convert, but would not have ever thought about it if not for this. He brought as proof a statement from Chazal that the warriors were all tzaddikim, and would not have been attracted by mere physical desirability.
Are there any commentators who say this?