soft about someone—(coll.) sentimentally silly about smb.; in love with a person:
- He’s too soft about the girl to see her faults.
soft on someone—
1. lacking sternness in one’s treatment of smb.; lenient towards a person:
- Many people think our courts are too soft on violent criminals.
2. = soft about someone:
- Ernie had an interest in my older sister. He was soft on her. She was quite attractive but not interested in him.
Note: The expression does not fully correlate in meaning with the phrase soft with someone— = soft on someone 1:
- Death penalty uncivilized? Maybe some think being too soft with criminals is the same thing as civility.