If you want to ask her out, make sure you’re on her radar first.

radar /ˈreɪdɑː(r)/ /ˈreɪdɑːr/

on/off somebody's/the radar (screen)

（不）受某人关注的；（不）受关注的

（if something is on your radar, you have noticed it and are giving it some attention；used to say that people’s attention is on or not on something）

• This is one of the issues on our radar. 这是我们所关注的事件之一。
• The issue of terrorism is back on the radar screen. 恐怖主义问题重新受人关注。
• Since the scandal broke, all other issues seem to have disappeared off the radar screen as far as the media is concerned.自丑闻爆发以来，就媒体而言，所有其他问题似乎已从雷达屏幕上消失了。
• A career in politics wasn't even on my radar (screen) at that point. [=I wasn't thinking at all about a career in politics]那时从政根本不在我的考虑范围内。

ask sb out

to invite someone to come with you to a place such as the cinema or a restaurant, especially as a way of starting a romantic relationship

（尤指为了开始与某人建立恋爱关系）请（某人）外出（或吃饭、看电影等）

• She's asked Steve out to the cinema this evening.她请了史蒂夫今晚出去看电影。
• You should ask her out sometime.你什么时候应该约她出来。