Men realize that popping the question will be one of the most important moments in a woman's life. Even if she says yes, there is still another issue that guys must contend with – making sure the ring fits. Engagement rings are the central element of the event, so men should make sure their fiancées can show off their new jewelry right away.
But how can this be done without clueing the woman in? Guys should know that just guessing at it is no good, because picking the wrong size will be uncomfortable and strange looking.
Jewelry Secrets reports that the first thing people should be aware of is that the fingers on the dominant hand tend to be a half a size larger than the non-dominant ones. So, if she's a lefty, you can't take your cues from a bauble she wears on her right hand. The source suggests that the best way to make sure you've got an accurate size is to ask her mother or another close female.
Women How-To also recommends pretending you're buying a ring for your mother or sister for a special occasion, then asking your girlfriend to model the styles because her hands are similar. Other options include secretly bringing one of her rings to the jewelers or measuring her finger with a slip of paper while she sleeps.