The second line of the shloka talks about the four hands. Two of the hands show the vara (boon) and abhaya (fearlessness) mudrAs. Earlier it was said in shloka #4 that all others other thanLalitAmbAL show the vara-abhaya mudrAs.
So in this shloka he presents Saraswati with the vara-abhaya mudrAs. The dual word ‘trAsa-trANa’ indicates the ‘abhaya’. For ‘trAsa’ means ‘fear’ and ‘trANa’ means protection. Protection from fear is just ‘abhaya’, fearlessness.