avec tous mes remerciements
with sincere gratitude in German is "in aufrichtiger Dankbarkeit"
The French word 'gratitude' is feminine.
remerciements
French: Gratitude Spanish: Gratitud
The correct spelling is "appreciation" (gratitude).
reconnaissance
The adjective sincere has only one spelling, sincere (frank, candid, honest, open).Words with similar spelling include censure (rebuke, condemnation) and sinecure (a position with benefits or powers, but usually no responsibilities).
The correct spelling is appreciation (thanks, gratitude).
The correct spelling is "appreciated" (shown gratitude).
You have only one letter wrong. It is gratitude.
The way you have it spelled in your question is as good as any - it's not really a word. Sincere is a word who's comparative and superlative are : more sincere, most sincere.
It means to thank someone for something in such a way that it sounds as if you think you don't deserve the thing for which you are thanking them. Gratitude is thankfulness. Humble gratitude doesn't necessarily mean to sound unworthy. It could be a sincere expression that there is no way to adequately repay the person for the thing or advantage given.