That's not a bad start, but it has a few problems. First, when a noun is the object of the preposition
in, the noun has to be in the ablative case; with
amor, that's
amore. (no pun intended

) Secondly,
audentia does have the meaning you want, but it's only rarely used; the more common word is
audacia, which means essentially the same thing. (But of course you could still use
audentia if you like the sound of it better.) So you could put it as follows:
In Amore Audacia.
You're right in observing that this literally means, "In love, boldness." If you wanted to stick closer to the English, you could say something like,
Audacter Amare, which is more literally "love boldly." But I kind of think
In Amore Audacia sounds better in Latin; phonetically too, it has a nice ring to it.
Let's see if other posters have comments or suggestions....