I hope that rather than suddenly engaging with the new girl, he disengages entirely and skedaddles to another town. He already got the new identity he needs, so he can spend some days in the current time to see if the situations improves soon while raising his rank and savings a tad, and if she doesnt desist by that time then he should flee. I don't think he needs to change identity yet again, as he isn't
that interesting to his stalker (a lot of issues for her to move city). He could of course try using her to gain magic knowledge and equipment, but that is frankly dangerous, and with how he left items related to his ex to a downright creepy degree ("its a sword I bought when I became adventurer with her... lets leave it!") I really doubt he would want to do that before leaving anyway.
@shunnie That last comment seems spoier-tagged for no reason? I saw hollows answer and took the risk to read it as it suggested as much, and seems to have been a warranted risk.