So, all this time when someone types /simper the game will say "[Person] smiles weakly at [person]".
Searching what simper means, it got definitions like "smile in an affectedly coquettish, coy, or ingratiating manner." or "an affectedly coquettish, coy, or ingratiating smile or gesture."
As a non-native English speaker, this was still too ambiguous for me still so I decided to further investigate what "coquettish" and "coy" meant, these were my results:
Coquettish - "behaving in such a way as to suggest a playful sexual attraction; flirtatious."
Coy - "making a pretense of shyness or modesty which is intended to be alluring." or "reluctant to give details about something regarded as sensitive."
Now I could be wrong here but the person using these emotes on me has a completely different translation (since they're French), on their side, they get "Lushiya Ikariname vous sourit tendrement". While "'Lushiya Ikariname' being my character name the rest means "smiles tenderly at you."

Edit:
I just find it weird how one translation has "smiles weakly" and the other has "smiles tenderly".

Thank you for the patience,
Lushiya Ikariname