to be sure
Certainly, undoubtedly, admittedly, surely.
I don't hate him. To be sure, we're not best buddies, but hate is a strong word.
VERBS
be, feel, seem, sound
My sister felt sure that she had locked the front door before leaving.
make
Before you leave the house, make sure you have your keys and phone with you.
make sb
His excellent test scores made his parents sure he would get into a good university.
ADV
absolutely, completely, damned, quite
doubly
He checked his work twice to be doubly sure before submitting it to his teacher.
not altogether, not entirely, not quite, not really
She's not entirely sure which train to catch on Saturday morning.
fairly, pretty
PREP
about
I'm not sure about the train schedule, so we should check online before leaving.
of
I'm not entirely sure of the restaurant's opening hours, so let me call them first.