have somebody’s interests at heart
US /hæv ˈsʌmˌbɑdiz ˈɪntrəsts æt hɑrt/
UK /hæv ˈsʌmˌbɑdiz ˈɪntrəsts æt hɑrt/

1.
to care about someone and want to help them in any way you can
:
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I know she always has my interests at heart, even when she's being tough.
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A good leader should always have their team's interests at heart.