I think we modern readers keep being tripped up by our own modern ideas of marriage, plus Elizabeth's pronouncement in P&P2 (which is nowhere in the novel) that "only the very deepest love" will persuade her to marry. IMO, it's clear that the Elizabeth of the novel does *not* insist on "true love" - at least not at the outset. What she insists on (which is revolutionary enough) is a man she can actually respect and like whom she can *grow* to love. If Wickham had had enough money for both of them to live on, and if he'd asked her, of course, IMO she would have married him if she hadn't found out what she did about his character.

Same goes for Col. Fitzwilliam. In ch.34, we have:

"(Elizabeth) could not think of Darcy's leaving Kent without remembering that his cousin was to go with him; but Colonel Fitzwilliam had made it clear that he had no intentions at all, and agreeable as he was, *she did not mean to be unhappy about him*."