SciFi/Fantasy - woman weilding a 'sword' with a weaponized black hole travels around with her bodyguard while ppl try to kill them and steal the sword thingy.

[Starlet]

I think the woman used to be a member of an interdimensional expedition or something but they all died one by one wandering and she is the last one. The bodyguard might have a crossbow or something; I think most of the people she meets have primitive weapons. Later on I think the 2 fall in love possibly. I seem to remember them traveling from portal to portal, trying to find her original home. The black hole sword thing should be enough to narrow it down a lot anyway.

I think I read it in the late 90s.

[Sue]

This makes me think of the Morgaine Chronicles by C J Cherry.
Gate of Ivrel the first one.
She had a sword with a strange power, though what that power was I do not remember, it’s ages since I read it, and was the last left alive of her companions. She also had a bodyguard.
Good luck, I hope you find your book!