Problem is, the name is something like “Hencha”.
What is the solution? Transliterate to Hadassah!! Period!!
There are two reasons to name a child for someone; for the deceased, and for the living. The ilui neshomo which comes through having someone named after you is, I’m told, only if the name is precise.
Nevertheless, as a way for the living to remember, it could be anything reminiscent of the person. It’s important to keep in mind, though, how the relatives will feel about an altered name.