How we cite our quotes: All quotations are from The Princess Bride.
Quote #1
GRANDSON: What is this? Are you trying to trick me? Where are the sports? Is this a kissing book?
Absolutely the grandfather was trying to trick his grandson. But he tricks him with nothing but the utmost love. There's no ill intent here; the grandfather clearly recognizes that his grandson is not going to mind kissing someday, and if he can be the one to change the kid's mind about it, then great. If not, well, there's probably a Hardy Boys book in his room somewhere.
Quote #2
INIGO: I am not left-handed.
All right, so this is barely a betrayal. Mainly because Inigo and Westley just met. However, when the fight starts and both men begin holding their swords with their non-dominant hands, they have already, in a sense, betrayed the trust of the other. That said, when engaging in a fight to the death, it's probably a good time to betray the other one's trust if you think it can give you an edge. All's fair in love and swordplay, right?
Quote #3
WESTLEY: Faithfulness he talked of, Madame, your enduring faithfulness. Now tell me truly, when you found out he was gone, did you get engaged to your prince at the same hour, or did you wait a whole week out of respect for the dead?
This is the major question of betrayal in the movie. Westley seems pretty steamed about Buttercup becoming engaged to Humperdinck in his absence, even when he has to know that it wasn't really her choice to do so. It's possible he was only giving her some grief about it before he revealed himself, but that doesn't seem like a very nice way to say hello to your true love after five years apart. He really sticks in the knife.