Formal:
* Ik hou van u, mama. (This is the most formal way to say it.)
Informal:
* Ik zie u graag, mama. (This is a common and affectionate way to say it.)
* Ik hou van jou, mama. (This is less formal than "Ik hou van u" and is more commonly used between family members.)
* Mama, ik hou van jou. (This is a very affectionate way to say it.)
Other options:
* Lieve mama, ik hou van jou. (This means "Dear Mom, I love you.")
* Ik hou ontzettend veel van jou, mama. (This means "I love you very much, Mom.")
Ultimately, the best way to say "I love you, Mom" in Flemish is the way that feels most natural and comfortable to you.