We do enjoy this – the extra word ‘do’ is used as emphasis.
Our little everyday verb 'do' performs ('does'!) almost surprisingly many duties in English, chiefly perhaps in its role as the emphatic auxiliary.
'We do enjoy this', and hope you will too in the following Quiz!
'I must' is not very confidence-inspiring, and 'I shall' is almost too formal; besides, neither of them echoes the phrasing of the question.