Formal:
* Avec amour - This is the most literal and straightforward translation.
* Tendrement - This translates to "tenderly" and conveys a softer, more affectionate feeling.
Informal:
* Bisous - This is a very common way to end a letter or note, meaning "kisses".
* Avec plein d'amour - This means "with lots of love" and is a more expressive way to show affection.
* Je t'embrasse - This means "I kiss you" and is a very personal way to end a letter.
You can also combine some of these phrases to create a more nuanced expression:
* Avec amour et tendresse - With love and tenderness
* Tendrement, et avec plein d'amour - Tenderly, and with lots of love
The best way to say "signed with love" in French depends on the context and your relationship with the recipient.