Fillers work well and have been used for years to successfully treat marionette lines. In this particular case, profile views of the jawline and frontal views of the cheeks would be helpful to determine which kind(s) and where best to inject the filler(s) in order to treat them. If there is volume deficit in the cheeks above, then treating this with a robust HA volumizing filler would not only create a more desirable, oval-shaped face, but would likely improve to some degree the marionette lines, which then can be more directly treated with the appropriate type and amounts of filler. Likewise, if there is significant sagging along the jawline, this, too, can be addressed with a robust filler and would likely secondarily improve the marionette lines, which can then be more directly treated. Direct treatment of the marionette lines, especially with ordinary fillers, such as plain Juvederm or Restylane, would be unlikely to result in satisfactory improvement. You would be wise to consult a board certified, cosmetic dermatologist and be sure to ask to see his/her personal before and after photos before agreeing to proceed. Best of luck.