Analysis.

(Remember: this analysis is particularly true about British language and culture, though mostly it is the same for other English-speaking countries like Australia and the United States.)

Sentence by Sentence analysis.

Sally: "A football club? You want to buy into a football club?"
(Sally repeats "football club" twice for emphasis. Note that the second part is a question even though it does not use the grammar of a question. Sally wants more than a "yes" or "no" answer, and this sentence suggests she want to talk about what seems a bad idea to her.)

Ivan: "Well, yes, I am considering it, in fact."
(This is a very defensive answer. Notice the verbal nulls "Well", "yes", and "in fact". Ivan uses these to hide the fact that he is giving very little information in his reply.)

Sally: "Well, it's your portfolio, but you are going to have to come up with some good reasons for the boss."
(Sally starts by admitting that she has no right to interfere with Ivan's portfolio, so she pretends that she is concerned that Ivan will not be able to give the boss a good reason for this investment.)

Ivan: "Oh, I have them."
(Ivan shows confidence. He says he has good reasons, but as Sally has said they are for the boss, there is no reason to tell Sally.)

Sally: "Yes, go on."
(Ivan's reply was very brief - a conversation-killer. But Sally still wants to know more, so she has to re-start the conversation. )

Ivan: "Oh, do you want to know too?"
(Ivan knows very well that Sally wants to know. He is pretending to be innocent to force Sally to admit she is being nosy. He is still slightly offended because Sally's opening question was so negative about his idea.)

Sally: "Yes, ok, I admit it. I want to know why you are buying into a football club. I mean, supporter interest always means that they are overpriced, and there is never any dividend to speak of. How do you intend to make a profit?"
(Sally surrenders. She admits her curiosity in detail so that Ivan cannot pretend not to know what she is talking about. Then she gives her reasons why she thinks it is a bad idea, hoping to encourage Ivan to explain why he thinks it is a good idea. To make sure he will do this, she follows with a direct question.)

Ivan:"I'll be honest with you - this is a bit of a gamble. But look at it like this. No-one in the city looks at football clubs, because they are bad value, right? But this club is coming out with a big share issue, even if they are doing it in two tranches, and the supporters are going to strain to buy it all up - that will keep the price down."
(Now that Sally is being open with him, Ivan opens up to. He admits there is a risk, and he begins to explain his thinking. )

Sally: "Maybe that is where it deserves to be."
(Shows that she is still unconvinced, but this is a comment, not a criticism. She is not attacking Ivan at this point.)

Ivan: "Ah, but this club have got Fettuchini playing as striker, and their first fixtures of the season are all against weak opposition. They might well be in the top ten for several weeks - then the share price will take off. "
(Ivan shows that he has been doing his research. He doesn't give details of the striker, as Sally can work out that he is very good from the context of the sentence - if she doesn't already know who he is.)

Sally: "Well, you seem to have it all thought out. I must admit it is not something I would have thought of, but that's why you are here, to give some fresh thinking."
(Sally admits that Ivan's argument is good. She also says that she would not do it, but suggests perhaps it is a good idea after all.)

Ivan: "As I said, it's a gamble. It could all go wrong. If it does, you can come to me and say "I told you so!"
(Ivan has persuaded Sally, but he is careful not to seem arrogant. He says again that his idea might be wrong, and Sally might be right.)

Sally: "I might do that. But still, pass me any interesting ideas you get about my stuff, would you?"
(Sally acknowleges that Ivan is being modest. She gives Ivan the right to discuss her portfolio with her. This is a compliment, because it shows that she thinks he can contribute something, and that she respects the way that he has behaved in the present discussion.)

Ivan: "If you want me to, of course."
(Is again careful not to be arrogant. He says that he will do what Sally wants. Both of them know that this means he should also mention when he thinks Sally has made a bad decision.)

Summary

Sally has questioned (rather rudely) whether it is a good idea for Ivan to invest in a football club. She tries to get Ivan to give his reasons, while pretending that she is not being nosy. Ivan refuses to let her do that, and so Sally admits that she wants to know because she is interested. Ivan then tells her everything. Sally admits that she thinks it is a good idea, but she still has doubts. But she is impressed enough to ask Ivan for any ideas about her own work. Since Ivan thinks so differently to her, he might find something she has not noticed. Ivan is happy to have proved his point, but is very careful not to offend Sally by saying she was wrong to be so critical at the start. Both of them are happy with the way that the other person has behaved in the conversation, so now they are more friendly, and they trust eachother a bit more.