If you spend more each month than you make, you will run a personal deficit.
If a country buys more than it sells, it will run a trade deficit.
One of the simplest determinants of whether or not a country is spending more than it makes is determined by its government accounts. If a government has a surplus, the country will tend to have a trade surplus; if a government runs a deficit, the country will tend to have a trade deficit. Generally - but not always - the government is big enough that it will cast the swing vote, if you will, as to whether the country as a whole spends more than it saves and, thus, runs a trade deficit or trade surplus.
Trump has called the Germans very bad because the US runs a trade deficit with Germany. Germany's government ran a government surplus of about $27 billion last year. The US federal government is projected run a deficit of about $400 billion and Trump's proposed budget would probably increase the debt by about $1.7 trillion over the next decade. Our government deficit loosely translates into a trade deficit.
Assuming that Trump has more influence over the US federal budget than he does over German consumers and companies, if he were sincere about reducing the trade deficit he would reduce the federal deficit.
Or he could send angry tweets that insist the real problem is Germans who save too much rather than a US government that can't agree on how to finance its spending.