I honestly don't care for any of them.
Basma - reminds me of plasma
Ibtisam / Ibtisama - both sound like gibberish and are extremely unwieldy
Basim - looks like a misspelling of
Basil, makes me think of "bosom" or "bassoon"
Basima - same complaints as
Basim
What about
Fariha or
Bahija? Both are feminine and mean "happy" in Arabic.
Farhan is a masculine alternative that also means "happy, cheerful."
http://www.behindthename.com/pnl/177263