Usage patterns
確かに〈事〉が、〈事〉it's true that ~, but ~ (concession)
It's true the price is high, but the quality is very good.
確かに〈事〉と言うto say for certain that ~
確かに〈物〉を見るto definitely see something (confirming a sighting)
I definitely saw him there.
Expressions
お気を確かにkeep calm; don't do anything rash; stay composed 気を確かに持つbrace oneself; keep one's composure; pull oneself together