«Would ~ Should»

[Xanthos]

Hello to everyone! I’m italian, and −at the present time− not very good at english. So, if you don’t mind, you could correct my sentences.

Here’s my question. What is the difference between «Why would I do that?» and «Why should I do that?»?

A: Please, don’t betray me!
B: Why would/should I do that?!

Is it the same meaning?

Thank you.

 

[abaka]

"Would", like "will", connotes desire. "Why would I do that?" asks if there's any reason for me to WANT to betray you.

"Should", like "shall", connotes obligation. "Why should I do that?" asks if there's anything that COMPELS me to betray you, regardless of whether I want to or not.

 

[Xanthos]

Clear! Thank you again.

 

[emsr2d2]

Remember to capitalise proper nouns: Italian and English.