The Pontiff, who is due to hold his first meeting with the US President at the Vatican later this month, said he would keep an open mind and not pass judgement on Mr Trump until first listening to his views.
"Even if one thinks differently we have to be very sincere about what each one thinks," Francis said.
"Topics will emerge in our conversations. I will say what I think and he will say what he thinks. But I have never wanted to make a judgement without first listening to the person."
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The Pope's meeting with Mr Trump could be potentially awkward given their diametrically opposed positions on immigration, refugees and climate change, which he said "are well known".
Last year, in response to a question about then-candidate Mr Trump's views on immigration and his intention to build a wall along the US border with Mexico, Francis said a man with such views was "not Christian".
Mr Trump, who grew up in a Presbyterian family, shot back saying it was "disgraceful" for the Pope to question his faith.
The two men also disagree strongly about climate change, with Mr Trump having signed an executive order dismantling Obama-era environmental legislation while Francis has made defence of the environment a key plank of his papacy, strongly backing scientific opinion that global warming is caused mostly by human activity.
Still, Francis said he was willing to find common ground with Mr Trump.
"There are always doors that are not closed. We need to find the doors that are at least partly open, go in, and talk about things we have in common and go forward, step by step," he said.