Trump did not suggest that NATO 'partners' pay or have to pay the USA at all! In fact NATO members are expected to spend a minimum of 2% of their individual GDP's on their own militaries, which can include direct and indirect funding to NATO itself.
"NATO is resourced through the direct and indirect contributions of its members. NATO’s common funds are composed of direct contributions to collective budgets and programmes, which equate to only 0.3% of total Allied defence spending (around EUR 3.3 billion for 2023). These funds enable NATO to deliver capabilities and run the entirety of the Organization and its military commands". https://www.nato.int/cps/en/natohq/topics_67655.htm
But, in fact, nearly 20 years after the agreement less than half NATO members are still yet to make the 2% mark.
https://commonslibrary.parliament.uk/defence-spending-pledges-by-nato-members-since-russia-invaded-ukraine/