She trusts him enough to send him a nude. OK....  but sending a nude is a wrong move however because she doesn't know how he feels about her: or Seto gets that she love him and she sends it because she trust him, or he believes that she just teases him and send a nude because she is a thot that plays with him... 
Ok, this is a lighthearted manga, so there will not consequences and it was a comical relief, but in RL this could get worse their relationship...