An SSL certificate will provide protection for your website. It will show customers that you want to keep them safe and secure and therefore should help to increase trust between buyer and seller. However, it can have a bigger effect on online business.
Many online shoppers know that they should look for certain signs to make sure that a website is safe to buy from. They will often look to see that there is a padlock within the browser frame to see that data is secure. They may also look for an https:// which is a secure web address. Some may look for a green address line as well. Having an SSL certificate could mean that these things will appear on your website. Which ones you have will be determined by the type of SSL certificate that you choose.
It is important to think about what your website is for and what sort of relationship you expect to have with your customers through the website. You need to think about the information that you want them to share with you and this will determine how secure you need the site to be. The more security that you have the more likely customers are to send this information. This means that if you are hoping to sell things through the website, you will need to make sure that they feel the site is secure enough for them to be prepared to send their personal information, especially their bank or credit card details. Without this security they may just decide not to buy anything from the website and the seller will lose out on significant amounts of business. This means that a certificate can help to show that the site is secure, increase the trust of the customers and therefore increase the online business.
Source: GoGet SSL Certificates