Hartelijk gefeliciteerd met jullie 28e trouwdag. Wij wensen jullie voor de toekomst een gelukkig, liefdevol en zorgeloos leven met jullie kinderen Luc en Tommy.
You can validate, Bilge, the translator just said she wasn't sure if "beaucoup d'amour" was used because she hasn't written any letter in French yet. If one's looking for a standard ("ready made" formula, then it is not very used but why not? Maybe adding "avec" before "beaucoup d'amour" would match the meaning as well, but IMO it is just fine as it is, I'd validate this translation with a good rating.