I'd be most grateful for your assistance with...

Meaning

I would be very thankful for your help with...

Examples

• John: 'I'd be most grateful for your assistance with this important task.'<br>
• Alice: 'I'd be happy to help you with that.'
• John: 'I'll do my best to help you.'
• Alice: 'I'd be most grateful for your assistance with this project.'<br>