Do you think Kate truly fell in love with Humphrey or was it just because of his howl?

It wasn't the Howl, it was the time they spent togheter... Their adventure togheter made her realize how great of a wolf Humphrey is. According to the movie, when wolves howl it's because they're in love, it's a sign of true love.

I do believe she loves Humphrey but I can see why some people might think the howl made her fall for him too by her facial expression when Humphrey howled.

I think she truly fell in love with him

she truly did

She probably had feelings for him but his howl and Humphrey's invite to howl with him probably also influenced her decision.

i think it was because of his howl idk i think

She truly love him :)