You can ask in a very "soft loving tone" no joke here...it is a writing technique...you use long vowel sounds with longer sentences, softer consenants (m,n,l etc)...it comes across as softer and more sincere...more loving

be prepared for a no

but is OK to ask

keep a smile on your face when you talk to her

if she says no, say, OK...the invitation is open for you to come again, just let me know and seque into a safer topic...don't let the sound of silence incriminate her...