I did, both in the books and in the show. I think Maragery was genuine in her desire to work the system (as she had been sent by her father to do) but also genuine in her affection for Sansa. Regarding their show relationship, which is likely what the dress homage is about, things are just a little more fleshed out because for one thing we get to see things from Margaery's perspective, unlike in the book. While we see in scenes between Margaery and her grandmother that she clearly doesn't like Joffrey and is only marrying him for political gain, we get not a single hint that she isn't being genuine in her friendship with Sansa. She's very open with Sansa (the talk about women getting to try so little before they're married), continues being sweet after her family's plan to marry Sansa to Loras gets scrapped, the rose (a yellow rose tipped in red signifies friendship), etc. Lots of little things. I appreciate that others may not have that same perspective, tho.
TBH, part of it is also just wanting that friendship. This show, and the books too, aren't very good at remembering that women can be friends with each other so there aren't that many female friendships to choose from. The show never gave me a reason to doubt Margaery's sincerity so I don't.