To engage another character in a dialogue, just press 
to present the available options.
Bribe[]
In dialogue, you can sometimes choose to Bribe someone. The Bribe option displays the amount of gold needed to successfully bribe the other character; if you can pay the price, the bribe succeeds.
The price of a bribe is based on your level and Speech skill. At higher levels, bribes become increasingly expensive, although a high Speech skill can offset this.
See also[]
Persuade[]
In dialogue, you can sometimes choose to Persuade someone. Your success at using the Persuade option depends on your Speech skill.
Apparel[]
Some articles of apparel help in dialogue situations: