I'm truly beholden to you.

John: 'I wouldn't have received this promotion without your guidance.'<br>

Alice: 'I'm truly beholden to you for your mentorship and support.'

John: 'I'm truly beholden to you for your timely assistance; I don't know what I would have done otherwise.'

Alice: 'Thanks to your intervention, the situation was resolved amicably.'<br>