I-adjective (keiyoushi)
joyful (news, event, etc.); joyous; delightful (e.g. result); pleasing (e.g. sight); gratifying; welcome; good; happy; glad; pleased
この喜ばしい日をお祝いし、幸せと喜びがあなたにきますように。May happiness and joy come to you as you celebrate this joyous day.
Also written 悦ばしい【よろこばしい】