to tell the truth
US /tə tel ðə truːθ/
UK /tə tel ðə truːθ/

1.
実を言うと, 正直に言うと
used to introduce a statement of fact or opinion, often one that is surprising or unexpected
:
•
To tell the truth, I don't really like his new song.
実を言うと、彼の新しい歌はあまり好きじゃない。
•
He said he was busy, but to tell the truth, he was just avoiding me.
彼は忙しいと言ったが、実を言うと、ただ私を避けていただけだった。