Apostrophes received as question marks when sending from apple mail
Hi,
I'm using a Mac Air, OSX 10.9.2.
I've configured Mail to work with my gmail account.
When sending emails adn using apostrophes (e.g. We're, they're, it's) the recipient (on a windows machine running Outlook) sees all the apostrophes as question marks.
Any ideas on settings? Rich Text vs Plain Text doesn't addres the issue.
Cheers
MacBook Air, OS X Mavericks (10.9.2)