how to read in user input ~/Downloads and resolve the ~?

[guyuming]

I need to read user input file path such as ~/Download with readline history, and resolve it with realpath.

however, the file_path variable value seems to have single quotation mark around it, so realpath says file not found in Chinese.

but if i echo $file_path, no single quotation mark shown.

How can I resolve user input from ~/Downloads into /home/guyuming/Downloads then?