Through his actions. Though being "in love" is very much different from love. Every boy is different and will show it through different ways. To really tell, you've got to know the boy, know and understand what he does. My boyfriend, he is a computer geek. One of the ways he shows his love to me is constantly helping me fix my laptop and computer, downloading, finding and installing programs I want, finding/downloading tv shows I might like, finding useful programs and add-ons for my digital art.