If you have an Intent and the other character doesn’t (aside from not wanting to gain your Intent), roll your skill against an Obstacle equal to his Will.
If you have an Intent and your opponent has an Intent, it’s a versus test and follows all the rules of versus tests. e.g., Persuasion vs. Persuasion.
Or if it’s something that’s important or relates to a Belief, go with a Duel of Wits.