[译] 我衷心祝贺你们婚姻幸福。
[误] I congratulate you wholeheartedly for your blissful marriage.

[正] I congratulate you wholeheartedly on your blissful marriage.
[注] 动词 congratulate 之后用介词 on，又如：I wish to congratulate you on your son’s entering the Beijing University. 您的儿子考取北京大学我表示祝贺。