I'm not shocked at all. In fact, I'm surprised that it's taken her so long to endorse Trump after dropping out of the election.
There's no one of character at all - that I know of at the national level in the Republican party - they've all quit or have been driven out of office.
Halley initially opposed Trump out of self-interest - now she's endorsing Trump for the very same reason.
What's worse is that Halley likely has very good insight into Trump's character and what he's capable of. No matter - it's expedient to endorse Trump for her own career - damn the consequences.