The full form of this name seems to be Yeab
Sera. Most frequent purported meaning/translation that I found with Google is "God's work".
I could not find a good confirmation for "Yeab" meaning God in Amharic, but it can be found in so many places connected to the
Christian faith that this seems quite probable, e.g. here on this page about Ethiopian prayers:
http://www.churchcloud.com/ace/sermons/
"
Sera" is even harder to confirm...
Rene www.BabyNames.ch