Gré comes from the Latin adjective gratis, grata, gratum which means pleasant, dear, loved or grateful, welcome or charming. In the GaffiotIt says "who receives a warm welcome".
To be grateful is precisely to be aware that something is pleasant.
When to use savoir gré?

The expression "savoir gré" is used to express gratitude or appreciation to someone. It can be used in a variety of ways, for example :
- I'm grateful for your help": this phrase means you're grateful for the help you've received from someone.
- "I'm grateful for your understanding": this expression shows that you're grateful for the understanding and empathy shown towards you. Saurai gré or serai gré? So there's no debate. Serai gré is incorrect.
Note that "savoir gré" is a verb. transitive (i.e. it refers to an object) indirect (it is introduced by a preposition of the type de, à, etc.), which means that it must be followed by an indirect object complement (COI) introduced by the preposition "de". For example: "I'm grateful to you from your benevolence".
I would be grateful or you would be grateful: mistakes not to be made
There are, however, some common mistakes when using the expression "savoir gré". Here are just a few examples:
- "Je sais vous gré pour votre aide": this sentence is incorrect, as "pour" can't be used as a preposition with "savoir gré". The correct usage would be "Je vous sais gré de votre aide".
Am I grateful or am I grateful?
The expression "suis gré" has no meaning in French and should not be used. As the French Academy "We'll be careful not to turn gré into an attributive adjective and substitute the verb to know for the verb to be...".
The expression is an old one, and also admits many variants around the word gré: one can know gré, know bon gré, know mauvais gré, and so on.
Would you like me to or would you like me to?
In practice, the use of this expression can sometimes prove disrespectful, when it is precisely the intention to show gratitude. For example, it's not uncommon to read in administrative correspondence "I'd be grateful if you'd fill in this form...", a form of injunction whose meaning can easily be understood in context.
Compare "In view of what has happened, in future, I would be grateful if you would refrain from speaking" and "I would be grateful if you would allow me a few minutes to discuss my proposal".
The use of the future tense sounds like an injunction that leaves no room for doubt. In the first case, let's say "in future, we'll ask you to keep quiet". In the second, "I'd like you to grant me an interview". Obviously, "if possible" is implied. Note in this example the deliberate use of "we" to easily distinguish the use of the future tense "we will ask you" from the conditional "we would ask you".
In a cover letter, to request an interview
So, in a letter of motivationDo not use the future tense. Use the conditional! For example, "I would be grateful if you could keep me informed of the outcome of my application...". If you want to use this expression to request an interview, never use the future tense. Don't say "I'll be grateful if you'll see me...", as your interviewer may well find out. unwillingly! By using the conditional tense, "I'd be grateful if you could tell me what steps I need to take to complete my file", you'll treat the person you're talking to with the deference they deserve.
Can we write "Je la sais grée "when talking about a woman?
No, gré remains invariable. Insofar as the expression is forged with know and not with be, gré is not an adjective and therefore cannot be a subject attribute or epithet. Just remember that even if you're talking about the person in charge of human resources who has given you the warmest welcome, you can't write: "I'm grateful to her.e for receiving me. You should write: I am grateful to her for having received me.
I'm grateful to you for an alternative
You can express gratitude by using "savoir gré", but the French language has many other ways of expressing gratitude.
If you don't feel comfortable with this expression, keep it simple. Instead, use a more common expression like "I'm grateful for..." but this time, make the agreement: if you're a woman, then write "I'm grateful for...".e... "
That's how Michel Serres began his address to the Académie française. acceptance speech January 31, 1991: "As an equivalent to the word remerciement [...] the French language has the terms grâce or gré, used indifferently in a masculine and gentle logic of free exchanges: je vous make my thanks or I'm grateful."
To find out more about using the future or conditional tense, click here: I could or I will or this way : je serai ou je serais !
Others tips for writing french correctly are available on the CVsansfaute blog.