I don’t think you know what the word “official” means. Because that’s definitely not true.

Last time I checked Trump wasn’t elected president of either of the countries involved so I would not bank on that promise. He might have some influence on both sides but yeah ultimately, unless he wants to directly involve the U.S. it’s not up to him when the war ends. Even if he completely withdraws U.S. support for Ukraine that still would not guarantee an end nor victory for his friend in Russia.