祈誓 is read as きせい (kisei) and means vow.
きせい
kisei
entreaty
せんせい
oath
せんしゅせんせい
athlete's oath of fair play
いのり
prayer
きがん
prayer (for something)
いのる
to wish
きとう
exorcism
きねん
いのりかい
prayer meeting
いのりもとめる
to pray for
ちかう
to swear
せいやく