Let me congratulate you on your success. ✬

I congratulate you on your engagement. ✬

Let me congratulate you on your marriage. ✬

Let me congratulate you on your engagement. ✬

I congratulate you on passing the examination. ✬

I congratulate you on winning first prize in the speech contest. ✬

I congratulate you on your success. ✬

I congratulate you on a job well done. ✬

I should congratulate you. ✬

I never got a chance to congratulate you. ✬