He puts you in your place

"Yes. I do. So you are the Beggar King. Come to seek aid for your wretched little kingdom. The kingdom that you are on the verge of losing to the Iron Born." Tywin stared at you over his steepled fingers eyes glinting like green ice as he continued almost daring you to interrupt. "The same Iron Born that my son-in-law crushed and smashed only a few short years ago. Yet they are apparently far too much for you to handle."

Rallying as you fight down your temper you attempt some flattery. "Robert Baratheon is a famed and mighty warrior and had the full might of the Seven Kingdom's behind him, including your wise counsel Lord Lannister..."

A single finger went up causing you to stop in your attempts at flattery. "Such arse licking would have worked upon my father ser. Do not attempt to play me for a fool. Or you might descend the mountain quicker than you ascended. Do you understand?"

Staring into those cold green eyes you knew without a shadow of a doubt he meant it. If you offended this man it could mean your death. The stories of the demises of House Reyne and Tarbeck suddenly seemed very real. As you nod slowly in acknowledgment he nods. "Good. So, you wish my help against the Iron Born. Ships, men, supplies and money. Basically gold. My gold. To defend your little island kingdom. So what is in it for me?"

"What do you want?" You ask bluntly, suspecting that is the best way to deal with the forceful Lord of Casterly Rock.

A mirthless chuckle erupts from a face that rarely smiles. "I have what I want King Rishard. My daughter is the Queen. My grandchild will be King. I am unchallenged within my lands and command both fear and respect and I am the richest man within the Seven Kingdoms."

"There must be something you want... Or else you wouldn't have met with me Lord Lannister." You guess shrewdly. "Name your desire and I swear as a King you shall have it!"