with (one's) whole heart
With one's sincerest feelings. I will love you with my whole heart until the day we die. I just wanted to tell you, with my whole heart, how proud I am of you.
with all your ˈheart/your whole ˈheart
used for emphasizing how strongly you feel about something: She hoped with all her heart that she would never have to see him again.I love you with all my heart.