Formal:
* Avec beaucoup d'amour: This is the most literal translation and is appropriate for formal situations.
* Avec tout mon amour: This means "with all my love" and can also be used in formal contexts.
Informal:
* Avec beaucoup d'affection: This means "with a lot of affection" and is more casual.
* Avec tout mon cœur: This means "with all my heart" and is very affectionate.
* Gros bisous: This is a very informal way to say "lots of love" and is often used among friends and family.
You can also use a combination of these phrases, such as "Avec beaucoup d'amour et de tendresse" (with a lot of love and tenderness).
Ultimately, the best way to say "With big love" in French depends on the specific situation and your relationship with the person you are speaking to.