How we cite our quotes: (Volume.Book.Chapter.Line)
Quote #4
[His] early years abroad, his migratory parents, his Swiss schools, his German university, as she had easy attention for. (1.2.2.30)
Poverty is not the only reason that Maud Lowder has a problem with Merton Densher. She also doesn't consider him to be quite "English" enough to marry her niece, Kate. Merton is a tough guy to pin down, and part of this might because of his unconventional upbringing. He has spent many years traveling with his parents and spent his university years in Germany. People in James' time would have been a bit wary of people educated abroad because they wouldn't quite know how to judge them. And, at least according to upper-crust English social code, people that didn't fall into a clear class bracket were untrustworthy.
Quote #5
The idea of his frivolity had, no doubt, to do with his personal designation, which represented […] a connection with an historic patriciate, a class that, in turn, also confusedly, represented an affinity with a social element that she had never heard otherwise described than as "fashion." (1.4.1.5)
Milly can see that Lord Mark comes from a long line of important British people. The man himself isn't all that wealthy, but he has the type of breeding that can only come from hundreds of years of familial wealth. In other words, social class isn't just based on money; it also is based on history.
Quote #6
"Mr. Merton, she holds […] won't ever be either a public man or a rich man. If he were public she'd be willing, as I understand, to help him; if he were rich—without being anything else—she'd do her best to swallow him." (1.4.3.33).
It's not like Merton needs to be rich to marry Kate. Aunt Maud would be just as satisfied if he were somebody important, like a politician or lord. But because Maud is convinced he'll never be rich or important, she has no interest in having him marry Kate.