Here's the translation of "I hate you" in Kannada:
ನನಗೆ ನಿನ್ನನ್ನು ದ್ವೇಷಿಸುತ್ತೇನೆ (Nanage ninnu dveshisautteene)
However, I strongly advise against using this phrase. Instead of expressing negativity, try to find more constructive ways to communicate your feelings.