if u want to improve the relation between u and ur friend, you need to use some money to do something with this friend.(跟朋友谈感情伤钱) AND if u want to count exactly the money between u and ur friend, for example, today u and ur friend have ur dinner together and u pay for it. after that, u say to ur friend: hey, you should give me half of the cost of the dinner. then what do ur friend think? he will think that u r not good, because u care about the money between u and ur friend even it is not much.(跟朋友谈钱伤感情) in china, among friends, normally, they don't care about money very much unless it is too much. for example, we are friends, and we have dinner together. I pay 20 yuan for both of us, u needn't pay. because we are friends, I know next time, u will pay for us. because we are friends. we say nothing but we do the things as the rule.

Ugh, well, a folksay, 谈感情=date with sb 伤钱=waste money 谈钱= talk sth about money, usually business stuff, or lend money 伤感情 hurt sb (mentally, feeling) just a folksay for rhyme