In html, you can do something like this
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent eget aliquet odio. Fusce id quam eu augu
Haml excels for structural markup, but it's not really intended for inline markup. Read: Haml Sucks for Content. Just put your inline tags as HTML:
.content %p Lorem ipsum dolor sit amet.
Or else use a filter:
.content :markdown Lorem ipsum *dolor* sit amet.