"I'm going to take care of that," he said, though he acknowledged that they would be difficult to convince.
In practice, though, it will be difficult to convince doubters that cash does not buy access to ministers.
"I think it'll be difficult to convince them to go anywhere near where the United States would like to go".
Mr Zajaczkowski admits it will be difficult to convince Poles to vote for UKIP because they are afraid of "being grabbed by the collar and kicked out".
"It will be difficult to convince large numbers of consumers to switch from conventionally powered passenger vehicles," J. D. Power said in a report in October.
Until that point it will always be difficult to convince VCs of the value of investing but there is always hope as Bike Citizens and UniGraph have shown.
Despite the Chinese government's new commitment to reducing meat consumption, it may be difficult to convince the country's rising middle classes to cut down.
But the outcome of this trial suggests that it may be difficult to convince a jury that he was not sufficiently mentally ill on the day of the attacks.
Conservatives, once intent on gutting Obamacare, have worked themselves into such a lather over the health-care law that it will be difficult to convince them to compromise the one-year delay is a compromise, they say.
While it might be difficult to convince investors that residential property here is a good bargain, the best example of the area's potential could well be the Tivadar Mika house.
It relies on subscription fees for its revenues, and given how many free sites there are, it can be difficult to convince parents that their $10 per month is money well spent.
