I’d go with Gaby’s solution (that checkmark looks the best!); but another way is to use a font-awesome icon in the text element. This way, you can edit the size and color of the checkmark as well. For example:
You can enter this into a text element:
Then you can use the Rich Text editor to adjust the color (and use a custom color code if you prefer). After editing the format in the rich text editor, the text becomes:
And the end result is:
*For this to work, you’ll also need to place a regular ‘icon’ somewhere on the page to allow Bubble to reference the font file.