How would you build her +def -hp

Her sturdy blow works fine but you can give her Swift Sparrow for more offence. Use steady breath for defense and her preferred B skill is wrath in either build, you can even keep her aether to have her heal massively in one hit for more sustain

That's a beauty.

Personally I'd use a defence set with steady/warding breath, aether vantage and a close defence seal to have her be the front wall of the team. With this set she'll charge aether very quickly and easily stays alive unless some green mage/dragon destroys her.
Of course a drive skill in her C.

An alternative for the B slot is quick reposte if you really want to make sure she doubles
Guard can work too.