"财政的承受能力" can be translated into English as "financial affordability" or "fiscal capacity to bear (the cost/burden)".
"Financial affordability" is a more general and concise term, often used to describe the ability to afford something financially without causing undue strain.
"Fiscal capacity to bear (the cost/burden)" is a more specific and formal expression, emphasizing the government's or organization's fiscal strength to handle financial burdens or costs.
In most contexts, especially when discussing government budgets or public policies, "financial affordability" would be a suitable and widely understood choice. If you need to emphasize the fiscal aspect more explicitly, you could use "fiscal capacity to bear" or a similar phrase.