I think Emma is really skittish of Frank putting her into the same kind of situation as Mr. Elton's proposal did in the carriage. She does not want to hurt him but I also think she wants to continue to receive friendly attentions from him. I agree that her vanity rationalizes his visit in a way that she need not be offended. I do not mean however to say it is all Emma’s vanity—she tickles my funny bone with her assurance he is in love with her but I think his attentions could be interpreted as favoring her rather than being in love with her. I don’t know why she takes Frank so seriously; maybe Mrs. and Mr. Weston’s hope she and Frank will get together influences how she views his behavior. (;D)