Help with translation correction please

A coworker is trying to write something to someone they've been seeing for a while. The person they're seeing is Venezuelan, so they want to learn to say it in Spanish for romantic effect. A couple of us have been trying to help, but none of us know Spanish.

So we have a few questions :

1. We got a few different translations from different apps. Which would be more correct? (see below)

2. Does heart dances and soul melts sound okay in Spanish, or would a different saying work better?

3. They've written 'my words dissappear' but I think what they're trying to say is 'words escape me'. Would the direct transations below be fine, or is there something else they can say there to express the same thing?

Original message in English

My heart dances when you look at me. My soul melts when you kiss me. My words disappear when you smile at me. But I need you to know that I love you.

Translation App 1

Mi corazón baila cuando me miras. Mi alma se derrite cuando me besas. Mis palabras desaparecen cuando me sonríes. Pero necesito que sepas que te amo.

Traslation App 2

Mi corazón baila cuando me miras. Mi alma se derrite cuando me besas. Lo que digo cuando me sonríes desaparece. Pero necesito que sepas que te amo.