In terms of Sally saying that Ben is going to marry her, I want to make it clear that I think Bernadette's interpretation of Sally and her acting choices are completely legitimate choices and I have no issues with the quality of her acting -- I just would have preferred a different take on Sally.
Bernadette's Sally, to me, seems to be genuinely mentally ill from the get go. Not foolish or silly or a bit "off," but genuinely mentally ill. It feels like Bernadette has chosen the title of "Losing My Mind" as the cornerstone to her interpretation. Sally seems to be completely disconnected from what Ben or anyone else is saying to her. I think that's why the "Ben wants to marry me" line came across to me as so absurd -- it doesn't seem like she is misinterpreting or giving a hopeful spin to what we've seen. I think in other productions I have seen, it didn't seem so completely ridiculous that Ben might have some type of feelings for Sally or that they have or had some type of connection. Here, I felt that we have seen nothing that would indicate that Sally would have any reason to feel that way, and her believing such a ridiculous thing was not grounded in any kind of reality.
It was as if she said something like, "I think I'm the daughter of Dmitri Weissman," which would have seemed about equally out of left field.
(Just my opinion, of course. I know others may disagree.)
"What was the name of that cheese that I like?"
"you can't run away forever...but there's nothing wrong with getting a good head start"
"well I hope and I pray, that maybe someday, you'll walk in the room with my heart"