have (one's) (best) interests at heart
To be primarily concerned with what would benefit one. I know you don't agree with some of the decisions I've made, but you have to trust that, as your mother, I have your best interests at heart.
have someone's best interest(s) at heart
to make decisions based on someone's best interests. I know she was only doing what would benefit her, but she said she had my best interests at heart.
have somebody’s (best) interests at ˈheart
want somebody to be happy and successful even though your actions may not show this: As a father, he always had his little girl’s best interests at heart.