Я не испытываю к тебе ненависти.

у меня нет ненависти к тебе

Thanks @Kirill

Hi, actually I can see a situation in which the phrase "Я не ненавижу тебя" can be used. As an example: I don't really like someone and that person feels this. And he asks me "What's wrong? Do you hate me?". I am not a good liar to say "nooo, I like you! why did you say such thing" instead I would probably say "No, I don't hate you" - Я не ненавижу тебя - and it will sound very unconvincing. Technically phrase "Я не ненавижу тебя" translates I don't hate you (or I don't dislike you), but in my opinion the meaning is "I don't hate you, but I don't like you either"